Document:

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                                                                    Exhibit 10.7

                                 PROMISSORY NOTE

U.S. $75,000,000.00                                      As of November 21, 2003

            FOR VALUE RECEIVED, and at the times hereinafter specified, KS
PARCEL D, LLC, a Delaware limited liability company ("Maker"), whose address is
101 Main Street, 18th Floor, Cambridge, Massachusetts 02142, hereby promises to
pay to the order of THE VARIABLE ANNUITY LIFE INSURANCE COMPANY, a Texas
corporation (hereinafter referred to, together with each subsequent holder
hereof, as "Holder"), at c/o AIG Global Investment Corp., 1 SunAmerica Center,
38th Floor, Century City, Los Angeles, California 90067-6022, or at such other
address as may be designated from time to time hereafter by any Holder, the
principal sum of SEVENTY-FIVE MILLION AND NO/100THS DOLLARS ($75,000,000.00),
together with interest on the principal balance outstanding from time to time,
as hereinafter provided, in lawful money of the United States of America.

            By its execution and delivery of this promissory note (this "Note"),
Maker covenants and agrees as follows:

            1. Interest Rate and Payments.

                  (a) The balance of principal outstanding from time to time
under this Note shall bear interest at the rate of six and thirty-eight
one-hundredths percent (6.38%) per annum (the "Original Interest Rate"), based
on a three hundred sixty (360) day year composed of twelve (12) months of thirty
(30) days each; provided, however, if any audit conducted by Genzyme Corporation
("Genzyme") pursuant to Section 3.1.1 of the Genzyme Lease shall result in a
reduction in the Annual Fixed Rent payable under such Genzyme Lease as of the
date of this Note (a "Rent Reduction") by more than five percent (5%). then,
commencing on the first day of the month following such Rent Reduction (the
"Rate Change Date"), the Original Interest Rate shall be adjusted in accordance
with the following formula: (i) if the Rent Reduction is greater than five
percent (5%), but less than or equal to ten percent (10%), then the Original
Interest Rate shall be increased by five one-hundredths percent (.05%), per
annum; (ii) if the Rent Reduction is greater than ten percent (10%), but less
than or equal to fifteen percent (15%), then the Original Interest Rate shall be
increased by fifteen one-hundredths percent (.15%), per annum; and (iii) if the
Rent Reduction is greater than fifteen percent (15%), then the Original Interest
Rate shall be increased by twenty five one-hundredths percent (.25%), per annum.

                  (b) Interest only shall be payable on the date the loan
evidenced by this Note (the "Loan") is funded by Holder, in advance, for the
period from and including the date of funding through and including November 30,
2003.

                  (c) Commencing on January 1, 2004 and on the first day of each
month thereafter through and including December 1, 2014, combined payments of
principal and interest (the "Regular Monthly Payment") shall be payable, in
arrears, in the amount of $500,796.03 each (such amount representing an amount
sufficient to fully amortize the original principal amount of this Note over a
twenty five (25) year period (the "Amortization Period"));provided, however, if
the Original Interest Rate is increased due to a Rent Reduction, as provided

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in Section 1 (a), above, then the Regular Monthly Payment shall be revised and,
commencing on the first day of the month following the Rate Change Date and on
the first day of each month thereafter through and including December 1, 2014,
combined payments of principal and interest shall be payable, in arrears, in an
amount sufficient to fully amortize the outstanding principal balance of the
Loan existing following the application of the monthly payment due on the Rate
Change Date over the remaining Amortization Period, at the revised Original
Interest Rate.

                  (d) Commencing on January 1, 2015 and on the first day of each
month thereafter through and including November 1, 2018, combined payments of
principal and interest shall be payable, in arrears, in an amount equal to the
sum of (i) the Regular Monthly Payment, plus (ii) $125,000.00 (such $125,000.00
shall be an additional principal payment and referred to herein as the "Required
Additional Payment").

                  (e) The entire outstanding principal balance, together with
all accrued and unpaid interest and all other sums due hereunder, shall be due
and payable in full on December 1, 2018 (the "Original Maturity Date");
provided, however, if any Rent Reduction shall result in a reduction in the
Annual Fixed Rent payable under the Genzyme Lease as of the date of this Note by
twenty percent (20%), or more (a "20% Rent Reduction"), then, at Holder's
option, the entire outstanding principal balance, together with all accrued and
unpaid interest and all other sums due hereunder, shall be due and payable
within ninety (90) days following demand.

            2. Holder's Extension Option; Net Operating Income.

                  (a) If Maker shall fail to pay the outstanding principal
balance of this Note and all accrued interest and other charges due hereon at
the Original Maturity Date, Holder shall have the right, at Holder's sole
option and discretion, to extend the term of the Loan for an additional period
of five (5) years (the "Extension Term"), in which case the entire outstanding
principal balance of this Note, together with all accrued interest and all other
sums due hereon, shall be due and payable in full on December 1, 2023. If Holder
elects to extend the term of the Loan, Maker shall pay all third-party fees of
Holder incurred in connection with such extension, including, but not limited
to, title insurance premiums and reasonable attorneys' fees. Maker shall execute
all documents reasonably requested by Holder to evidence and secure the Loan, as
extended, and shall obtain and provide to Holder any title insurance policy or
endorsement requested by Holder.

                  (b) Should Holder elect to extend the term of the Loan as
provided above, Holder shall (i) reset the interest rate borne by the
then-existing principal balance of the Loan to a rate per annum (the "New Rate")
equal to the greater of (A) the Original Interest Rate, or (B) Holder's (or
comparable lenders', if Holder is no longer making such loans) then-prevailing
interest rate for five (5) year loans secured by properties similar to the
Property(hereinafter defined), as determined by Holder in its sole discretion;
(ii) re-amortize the then-existing principal balance of the Loan over the
remaining portion of the Amortization Period (the "New Amortization Period");
(iii) have the right to require Maker to enter into modifications of the
non-economic terms of the Loan Documents as Holder may request to reflect such
extension (the "Non-Economic Modifications"); and (iv) notwithstanding any
provision set forth in the Loan Documents to the contrary, have the right to
require Maker to

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make monthly payments into escrow for insurance premiums and real property
taxes, assessments and similar governmental charges. Hence, monthly principal
and interest payments' during the Extension Term shall be based upon the New
Rate, and calculated to amortize fully the outstanding principal balance of the
Loan over the New Amortization Period.

                  (c) If Holder elects to extend the term of the Loan, Holder
shall advise Maker of the New Rate on or prior to the Original Maturity Date.

                  (d) In addition to the required monthly payments of principal
and interest set forth above, commencing on the first day of the second month
following the Original Maturity Date and continuing on the first day of each
month thereafter during the Extension Term (each an "Additional Payment Date"),
Maker shall make monthly payments to Holder in an amount equal to all Net
Operating Income (hereinafter defined) attributable to the Property for the
calendar month ending on the last day of the month that is two months preceding
each such Additional Payment Date. For example, assuming the Original Maturity
Date is January 1, then Net Operating Income for the period from January 1
through January 31 shall be payable to Holder on March 1; Net Operating Income
for the period from February 1 through February 28 shall be payable to Holder on
April 1, and so on.

                  (e) Holder shall deposit all such Net Operating Income
received from Maker into an account or accounts maintained at a financial
institution chosen by Holder or its servicer in its sole discretion (the
"Deposit Account") and all such funds shall be invested in a manner acceptable
to Holder in its sole discretion. All interest, dividends and earnings credited
to the Deposit Account shall be held and applied in accordance with the terms
hereof.

                  (f) On the third Additional Payment Date and on each third
Additional Payment Date thereafter, Holder shall apply all Excess Funds
(hereinafter defined), if any, to prepayment of amounts due under this Note,
without premium or penalty.

                  (g) As security for the repayment of the Loan and the
performance of all other obligations of Maker under the Loan Documents, Maker
hereby assigns, pledges, conveys, delivers, transfers and grants to Holder a
first priority security interest in and to: all Maker's right, title and
interest in and to the Deposit Account; all rights to payment from the Deposit
Account and the money deposited therein or credited thereto (whether then due or
in the future due and whether then or in the future on deposit); all interest
thereon; any certificates, instruments and securities, if any, representing the
Deposit Account; all claims, demands, general intangibles, choses in action and
other rights or interests of Maker in respect of the Deposit Account; any monies
then or at any time thereafter deposited therein; any increases, renewals,
extensions, substitutions and replacements thereof; and all proceeds of the
foregoing.

                  (h) From time to time, but not more frequently than monthly,
Maker may request a disbursement (a "Disbursement") from the Deposit Account for
capital expenses, tenant improvement expenses, leasing commissions and special
contingency expenses. Holder may consent to or deny any such Disbursement in its
sole discretion.

                  (i) Upon the occurrence of any Event of Default (hereinafter
defined) (i) Maker shall not be entitled to any further Disbursement from the
Deposit Account; and

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(ii) Holder shall be entitled to take immediate possession and control of the
Deposit Account (and all funds contained therein) and to pursue all of its
rights and remedies available to Holder under the Loan Documents, at law and in
equity.

                  (j) All of the terms and conditions of the Loan shall apply
during the Extension Term, except as expressly set forth above, and except that
no further extensions of the Loan shall be permitted.

                  (k) For the purposes of the foregoing:

                        (i) "Excess Funds" shall mean, on any Additional Payment
            Date, the amount of funds then existing in the Deposit Account
            (including any Net Operating Income due on the applicable Additional
            Payment Date), less an amount equal to the sum of three regularly
            scheduled payments of principal and interest due on this Note;

                        (ii) "Net Operating Income" shall mean, for any
            particular period of time, Gross Revenue for the relevant period,
            less Operating Expenses for the relevant period; provided, however,
            that if such amount is equal to or less than zero (0), Net Operating
            Income shall equal zero (0);

                        (iii) "Gross Revenue" shall mean all payments and other
            revenues (exclusive, however, of any payments attributable to sales
            taxes) received by or on behalf of Maker from all sources related to
            the ownership or operation of the Property, including, but not
            limited to, rents, room charges, parking fees, interest, security
            deposits (unless required to be held in a segregated account),
            business interruption insurance proceeds, operating expense
            pass-through revenues and common area maintenance charges, for the
            relevant period for which the calculation of Gross Revenue is being
            made; and

                        (iv) "Operating Expenses" shall mean the sum of all
            necessary operating expenses actually paid by Maker in connection
            with the operation of the Property during the relevant period for
            which the calculation of Operating Expenses is being made,
            including, but not limited to, (a) payments made by Maker for taxes
            and insurance required under the Loan Documents, and (b) monthly
            debt service payments as required under this Note.

            3. Budgets During Extension Term.

                  (a) Within fifteen (15) days following the Original Maturity
Date and on or before December 1 of each subsequent calendar year, Maker shall
deliver to Holder a proposed revenue and expense budget for the Property for the
remainder of the calendar year in which the Original Maturity Date occurs or the
immediately succeeding calendar year (as applicable). Such budget shall set
forth Maker's projection of Gross Revenue and Operating Expenses for the
applicable calendar year, which shall be subject to Holder's reasonable
approval. Once a proposed budget has been reviewed and approved by Holder, and
Maker has made all revisions requested by Holder, if any, the revised budget
shall be delivered to Holder and shall thereafter become the budget for the
Property hereunder (the "Budget") for the

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applicable calendar year. If Maker and Holder are unable to agree upon a Budget
for any calendar year, the budgeted Operating Expenses (excluding extraordinary
items) provided in the Budget for the Property for the preceding calendar year
shall be considered the Budget for the Property for the subject calendar year
until Maker and Holder agree upon a new Budget for such calendar year.

                  (b) During the Extension Term, Maker shall operate the
Property in accordance with the Budget for the applicable calendar year, and the
total of expenditures relating to the Property exceeding one hundred and five
percent (105%) of the aggregate of such expenses set forth in the Budget for the
applicable time period shall not be treated as Operating Expenses for the
purposes of calculating "Net Operating Income," without the prior written
consent of Holder except for emergency expenditures which, in the Maker's good
faith judgment, are reasonably necessary to protect, or avoid immediate danger
to, life or property.

            4. Reports During Extension Term.

                  (a) During the Extension Term, Maker shall deliver to Holder
all financial statements reasonably required by Holder to calculate Net
Operating Income, including, without limitation, a monthly statement to be
delivered to Holder concurrently with Maker's payment of Net Operating Income
that sets forth the amount of Net Operating Income accompanying such statement
and Maker's calculation of Net Operating Income for the relevant calendar month.
Such statements shall be certified by an executive officer of Maker or Maker's
manager, managing member or general partner (as applicable) as having been
prepared in accordance with the terms hereof and to be true, accurate and
complete in all material respects.

                  (b) In addition, on or before February 1 of each calendar year
during the Extension Term, Maker shall submit to Holder an annual income and
expense statement for the Property which shall include the calculation of Gross
Revenue, Operating Expenses and Net Operating Income for the preceding calendar
year and shall be accompanied by Maker's reconciliation of any difference
between the actual aggregate amount of the Net Operating Income for such
calendar year and the aggregate amount of Net Operating Income for such calendar
year actually remitted to Holder. All such statements shall be certified by an
executive officer of Maker or Maker's manager, managing member or general
partner (as applicable) as having been prepared in accordance with the terms
hereof and to be true, accurate and complete in all material respects. If any
such annual financial statement discloses any inconsistency between the
calculation of Net Operating Income and the amount of Net Operating Income
actually remitted to Holder, Maker shall immediately remit to Holder the amount
of any underpayment of Net Operating Income for such calendar year or, in the
event of an overpayment by Maker, such amount may be withheld from any
subsequent payment of Net Operating Income required hereunder.

                  (c) Holder may notify Maker within ninety (90) days after
receipt of any statement or report required hereunder that Holder disputes any
computation or item contained in any portion of such statement or report. If
Holder so notifies Maker, Holder and Maker shall meet in good faith within
twenty (20) days after Holder's notice to Maker to resolve such disputed items.
If, despite such good faith efforts, the parties are unable to resolve the
dispute at such meeting or within ten (10) days thereafter, the items shall be
resolved by an

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independent certified public accountant designated by Holder (and approved by
Maker, such approval not to be unreasonably withheld) within fifteen (15) days
after such ten (10) day period; It shall be reasonable for Maker to withhold
consent to Holder's designation of an accountant if using such accountant would
cause a conflict of interest concern for or violation of any auditing or
accounting regulations or standards by any of the direct or indirect owners of
Maker under the regulations of the United States Securities Exchange Commission
or any similar regulatory body in the United States or United Kingdom. The
determination of such accountant shall be final. All fees of such accountant
shall be paid by Maker. Maker shall remit to Holder any additional amount of Net
Operating Income found to be due for such periods within ten (10) days after the
resolution of such dispute by the parties or the accountant's determination, as
applicable. The amount of any overpayment found to have been made for such
periods may be withheld from any required future remittance of Net Operating
Income.

                  (d) Maker shall at all times keep and maintain full and
accurate books of account and records adequate to reflect correctly all items
required in order to calculate Net Operating Income.

            5. Prepayment.

                  (a) At any time during the term of the Loan, Maker shall have
the right to prepay the full principal amount of this Note and all accrued but
unpaid interest hereon as of the date of prepayment, provided that (i) Maker
gives not less than thirty (30) days' prior written notice to Holder of Maker's
election to prepay this Note, and (ii) Maker pays a prepayment premium to Holder
equal to (A) during the first two (2) years after the date of this Note (the
"First Prepayment Period"), the greater of (1) two percent (2%) of the
outstanding principal amount of this Note, or (2) one hundred fifty percent
(150%) of the Present Value of this Note(hereinafter defined), less the amount
of principal being prepaid, calculated as of the prepayment date, and (B) at any
time following the First Prepayment Period, the greater of(1) one percent (1%)
of the outstanding principal amount of this Note, or (2) the Present Value of
this Note, less the amount of principal being prepaid, calculated as of the
prepayment date.

                  (b) Holder shall notify Maker of the amount and basis of
determination of the prepayment premium. Holder shall not be obligated to accept
any prepayment of the principal balance of this Note unless such prepayment is
accompanied by the applicable prepayment premium and all accrued interest and
other sums due under this Note. Maker may not prepay the Loan on a Friday or on
any day preceding a public holiday, or the equivalent for banks generally under
the laws of the Commonwealth of Massachusetts.

                  (c) Except for making payments of Net Operating Income during
the Extension Term as required above, and except for the application of
insurance proceeds or condemnation awards to the principal balance of this Note,
as provided in the Mortgage(hereinafter defined), in no event shall Maker be
permitted to make any partial prepayments of this Note.

                  (d) If Holder accelerates this Note for any reason, then in
addition to Maker's obligation to pay the then outstanding principal balance of
this Note and all accrued but unpaid interest thereon, Maker shall pay an
additional amount equal to the prepayment premium

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that would be due to Holder if Maker were voluntarily prepaying this Note at the
time that such acceleration occurred.

                  (e) For the purposes of the foregoing:

                        (i) The "Present Value of this Note" with respect to any
            prepayment of this Note, as of any date, shall be determined by
            discounting all scheduled payments of principal and interest
            remaining to maturity of this Note, attributed to the amount being
            prepaid, at the Discount Rate (hereinafter defined). If prepayment
            occurs on a date other than a regularly scheduled payment date, the
            actual number of days remaining from the prepayment date to the next
            regularly scheduled payment date will be used to discount within
            such period;

                        (ii) The "Discount Rate" is the rate which, when
            compounded monthly, is equivalent to the Treasury Rate, when
            compounded semi-annually, plus twenty-five (25) basis points;

                        (iii) The "Treasury Rate" is the semi-annual yield on
            the Treasury Constant Maturity Series with maturity equal to the
            remaining weighted average life of this Note, for the week prior to
            the prepayment date, as reported in Federal Reserve Statistical
            Release H.15 - Selected Interest Rates, conclusively determined by
            Holder on the prepayment date. The rate will be determined by linear
            interpolation between the yields reported in Release H.15, if
            necessary. In the event Release H.15 is no longer published, Holder
            shall select a comparable publication to determine the Treasury
            Rate.

                  (f) Holder shall not be obligated actually to reinvest the
amount prepaid in any treasury obligations as a condition precedent to receiving
any prepayment premium.

                  (g) Notwithstanding the foregoing, (i) during the three (3)
month period immediately preceding the Original Maturity Date and at any time
during the Extension Term, Maker shall have the right to prepay the full
principal amount of this Note and all accrued but unpaid interest thereon as of
the date of prepayment, without prepayment premium thereon,(ii) no prepayment
premium shall be due in connection with the application of any insurance
proceeds or condemnation awards to the principal balance of this Note, as
provided in the Mortgage, and (iii) no prepayment premium shall be due in
connection with any Required Additional Payment.

            6. Payments. Whenever any payment to be made under this Note shall
be stated to be due on a Saturday, Sunday or public holiday or the equivalent
for banks generally under the laws of the Commonwealth of Massachusetts (any
other day being a "Business Day"),such payment may be made on the next
succeeding Business Day.

            7. Default Rate.

                  (a) The entire balance of principal, interest, and other sums
due upon the maturity hereof, by acceleration or otherwise, shall bear interest
from the date due until paid

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at the greater of (i) eighteen percent (18%) per annum and (ii) a per annum rate
equal to five percent (5%) over the prime rate (for corporate loans at large
United States money center commercial banks) published in The Wall Street
Journal on the first business day of each month (the "Default Rate"); provided,
however, that such rate shall not exceed the maximum permitted by applicable
state or federal law. In the event The Wall Street Journal is no longer
published or no longer publishes such prime rate, Holder shall select a
comparable reference.

                  (b) If any payment under this Note is not made within five (5)
days after the date such payment becomes due, interest on the outstanding
principal balance of this Note shall accrue at the Default Rate from such fifth
(5th) day after such payment was due until payment is actually made.

            8. Late Charges. In addition to interest as set forth herein, Maker
shall pay to Holder a late charge equal to four percent (4%) of any monthly
payment amounts due under this Note in the event any such amount is not paid
within five (5) days after the date such payment becomes due.

            9. Application of Payments. All payments hereunder shall be applied
first to the payment of late charges, if any, then to the payment of prepayment
premiums, if any, then to the repayment of any sums advanced by Holder for the
payment of any insurance premiums, taxes, assessments, or other charges against
the property securing this Note (together with interest thereon at the Default
Rate from the date of advance until repaid), then to the payment of accrued and
unpaid interest, and then to the reduction of principal.

            10. Immediately Available Funds. Payments under this Note shall be
payable in immediately available funds without setoff, counterclaim or deduction
of any kind, and shall be made by electronic funds transfer from a bank account
established and maintained by Maker for such purpose.

            11. Security. This Note is secured by a Mortgage, Security
Agreement, Fixture Filing, Financing Statement and Assignment of Leases and
Rents of even date herewith granted by Maker for the benefit of the named Holder
hereof (the "Mortgage") encumbering certain real property and improvements
thereon commonly known as 500 Kendall Street, Cambridge, Massachusetts as more
particularly described in such Mortgage (the "Property").

            12. Certain Definitions. Capitalized terms used herein and not
otherwise defined shall have the meanings set forth in the Mortgage.

            13. Event of Default. Each of the following events will constitute
an event of default (an "Event of Default") under this Note and under the
Mortgage and each other Loan Document, and any Event of Default under any Loan
Document shall constitute an Event of Default hereunder and under each of the
other Loan Documents:

                  (a) any failure to pay when due any sum hereunder; provided,
however, that Maker shall be permitted to make one (1) payment hereunder
within-five (5) days following its due date in any consecutive twelve (12) month
period without such event constituting an Event of Default;

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                  (b) any failure of Maker to properly perform any obligation
contained herein or in any of the other Loan Documents (other than the
obligation to make payments under this Note or the other Loan Documents) and
the continuance of such failure for a period of thirty (30) days following
written notice thereof from Holder to Maker; provided, however, that if such
failure is not curable within such thirty (30) day period, then, so long as
Maker commences to cure such failure within such thirty (30) day period and is
continually and diligently attempting to cure to completion, such failure shall
not be an Event of Default unless such failure remains uncured for one hundred
twenty (120) days after such written notice to Maker; provided, further, that if
Holder shall so elect in the exercise of its sole but good faith discretion,
then after such 120 day period, and for so long as Maker is continually and
diligently attempting to cure to completion, such failure shall not be an Event
of Default so long as Maker provides to Holder such additional security to
adequately protect Holder as is acceptable to Holder in the exercise of its sole
but good faith discretion; or

                  (c) if, at any time during the Extension Term, Gross Revenue
for each of any two consecutive calendar months shall be less than ninety-three
percent (93%) of the amount of projected Gross Revenue for such months set forth
in the applicable Budget.

            14. Acceleration. Upon the occurrence of any Event of Default, the
entire balance of principal, accrued interest, and other sums owing hereunder
shall, at the option of Holder, become at once due and payable without notice or
demand. Upon the occurrence of an Event of Default described in SECTION 13(c)
hereof, Holder shall have the option, in its sole discretion, to either (a)
exercise any remedies available to it under the Loan Documents, at law or in
equity, or (b) require Maker to submit a new proposed budget for Holder's
approval. If Holder agrees to accept such new proposed budget, then such budget
shall become the Budget for all purposes hereunder.

            15. Conditions Precedent. Maker hereby certifies and declares that
all acts, conditions and things required to be done and performed and to have
happened precedent to the creation and issuance of this Note, and to constitute
this Note the legal, valid and binding obligation of Maker, enforceable in
accordance with the terms hereof, have been done and performed and happened in
due and strict compliance with all applicable laws.

            16. Certain Waivers and Consents. Maker and all parties now or
hereafter liable for the payment hereof, primarily or secondarily, directly or
indirectly, and whether as endorser, guarantor, surety, or otherwise, hereby
severally (a) waive presentment, demand, protest, notice of protest and/or
dishonor, and all other demands or notices of any sort whatever with respect to
this Note, (b) consent to impairment or release of collateral, extensions of
time for payment and acceptance of partial payments before, at, or after
maturity, (c) waive any right to require Holder to proceed against any security
for this Note before proceeding hereunder, (d) waive diligence in the collection
of this Note or in filing suit on this Note, and (e) agree to pay all costs and
expenses, including reasonable attorneys' fees, which may be incurred in the
collection of this Note or any part thereof or in preserving, securing
possession of, and realizing upon any security for this Note.

            17. Usury Savings Clause. The provisions of this Note and of all
agreements between Maker and Holder are, whether now existing or hereinafter
made, hereby expressly

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limited so that in no contingency or event whatever, whether by reason of
acceleration of the maturity hereof, prepayment, demand for payment or
otherwise, shall the amount paid, or agreed to be paid, to Holder for the use,
forbearance, or detention of the principal hereof or interest hereon, which
remains unpaid from time to time, exceed the maximum amount permissible under
applicable law, it particularly being the intention of the parties hereto to
conform strictly to Massachusetts and Federal law, whichever is applicable. If
from any circumstance whatever, the performance or fulfillment of any provision
hereof or of any other agreement between Maker and Holder shall, at the time
performance or fulfillment of such provision is due, involve or purport to
require any payment in excess of the limits prescribed by law, then the
obligation to be performed or fulfilled is hereby reduced to the limit of such
validity, and if from any circumstance whatever Holder should ever receive as
interest an amount which would exceed the highest lawful rate, the amount which
would be excessive interest shall be applied to the reduction of the principal
balance owing hereunder (or, at Holder's option, be paid over to Maker) and
shall not be counted as interest. To the extent permitted by applicable law,
determination of the legal maximum amount of interest shall at all times be made
by amortizing, prorating, allocating and spreading in equal parts during the
period of the full stated term of this Note, all interest at any time contracted
for, charged, or received from Maker in connection with this Note and all other
agreements between Maker and Holder, so that the actual rate of interest on
account of the indebtedness represented by this Note is uniform throughout the
term hereof.

            18. Non-Recourse; Exceptions to Non-Recourse. Nothing contained in
this Note or any of the other Loan Documents shall be deemed to impair or limit
Holder's rights: in foreclosure proceedings or in any ancillary proceedings
brought to facilitate Holder's foreclosure on the Property or any portion
thereof or to exercise any specific rights or remedies afforded Holder under any
other provisions of the Loan Documents or by law or in equity, subject to the
non-recourse provisions set forth below; to recover under any guarantee given in
connection with the Loan; or to pursue any personal liability of Maker or any
Guarantor under the Environmental Indemnity Agreement or Section 5.10 of the
Mortgage. Except as expressly set forth in this Section 18, the recourse of
Holder with respect to the obligations evidenced by this Note shall be solely to
the Property, Chattels and Intangible Personality (as defined in the Mortgage)
and any other collateral given as security for the Loan:

                  (a) Notwithstanding anything to the contrary contained in this
      Note or in any Loan Document, nothing shall be deemed in any way to
      impair, limit or prejudice the rights of Holder to collect or recover from
      Maker: (i) damages or costs (including without limitation reasonable
      attorneys' fees) incurred by Holder as a result of waste by Maker; (ii)
      any condemnation or insurance proceeds attributable to the Property which
      were not paid to Holder or used to restore the Property in accordance with
      the terms of the Mortgage; (iii) any rents, profits, advances, rebates,
      prepaid rents or other similar sums attributable to the Property collected
      by or for Maker following an Event of Default (as defined in the Mortgage)
      and not properly applied to the reasonable fixed and operating expenses of
      the Property, including payments of this Note and other sums due under the
      Loan Documents; (iv) any security deposits collected by or for Maker and
      not applied in accordance with applicable leases; (v) the amount of any
      accrued taxes, assessments, and/or utility charges affecting the Property
      (whether or not the same have been billed to Maker) that are either unpaid
      by Maker or advanced by Holder under the Mortgage: (vi) any sums expended
      by Holder in fulfilling the obligations of Maker, as

                                       10
<PAGE>

      lessor, under any leases affecting the Property; and (vii) the amount of
      any loss suffered by Holder (that would otherwise be covered by insurance)
      as a result of Maker's failure to maintain the insurance required under
      the terms of any Loan Document. Notwithstanding the foregoing, Maker shall
      not be personally liable for (A) taxes or utility charges relating to the
      period after the date (the "Transfer Date") which is the earlier to occur
      of (1) the date the Holder takes title to the Property in connection with
      the foreclosure of the Mortgage, and (2) the date on which the Maker
      tenders to Holder a deed in lieu of foreclosure for the Property, whether
      or not it is accepted by Holder (provided that such deed contains no
      changes to the title not previously approved in writing by Holder since
      the Loan closing and that there are no Hazardous Substances as defined in
      the Environmental Indemnity Agreement unlawfully present on the Property),
      (B) any taxes accruing prior to the Transfer Date to the extent of amounts
      on deposit in any real estate escrow account required under the Loan
      Documents plus any amounts actually collected by Holder from tenants at
      the Property which are payable as tenants' share of real estate taxes
      accruing prior to the Transfer Date, or (C) any sums expended by Holder in
      fulfilling the obligations of Maker, as lessor, under any leases affecting
      the Property accruing after the Transfer Date;

                  (b) The agreement set forth in the introductory paragraph of
      this Section 18 to limit the personal liability of Maker shall become null
      and void and be of no further force and effect, and Maker and each
      Guarantor shall be personally liable for the obligations evidenced by this
      Note, in the event (i) that the Property, or any part thereof or any
      interest therein, or any interest in Maker, shall be further encumbered by
      a voluntary lien securing any obligation upon which Maker, any direct or
      indirect general partner, manager or managing member of Maker, any
      guarantor of the Loan, or any principal or affiliate of Maker shall be
      personally liable for repayment, either as obligor or guarantor; (ii) of
      any breach or violation of Section 5.4, 5.5 or 5.7 of the Mortgage; (iii)
      of any fraud or misrepresentation by Maker in connection with the
      Property, the Loan Documents or the application made by Maker for the
      Loan; (iv) that Maker forfeits the Property or Chattels or any portion of
      the Property or Chattels due to criminal activity; (v) of any attempt by
      Maker, any Guarantor, or any other person directly or indirectly
      responsible for the management of Maker or liable for repayment of Maker's
      obligations under the Loan (whether as maker, endorser, guarantor, surety,
      general partner or otherwise) to willfully and materially delay any
      foreclosure against the Property, Chattels and/or Intangible Personalty
      or any other exercise by Holder of its remedies under the Loan Documents,
      which attempts shall include, without limitation, (A) any claim that any
      Loan Document is invalid or unenforceable to an extent that would preclude
      any such foreclosure or other exercise of remedies, (B) Maker filing a
      petition In bankruptcy, Maker failing to oppose in good faith the entry of
      an order for relief pursuant to any involuntary bankruptcy petition filed
      against it or Maker seeking any reorganization, liquidation, dissolution
      or similar relief under the bankruptcy laws of the United Slates or under
      any other similar federal, state or other statute relating to relief from
      indebtedness, or (C) the appointment of a receiver, trustee or liquidator
      with respect to Maker or the Property or any part thereof; (vi) of any
      amendment, modification or voluntary termination of the Genzyme Lease (as
      such term is defined in the Mortgage) or of any execution or subsequent
      amendment, modification or termination of any lease for any space
      currently demised under the Genzyme Lease in excess of 25,000 square feet,

                                       11
<PAGE>

      without the prior written consent of Holder; (vii) of any modification
      without Holder's prior written consent, or the termination for any reason,
      of the Parking Lease (as defined in the Mortgage); or (viii) of a 20% Rent
      Reduction. For purposes of the foregoing, "affiliate" shall mean any
      individual, corporation, trust, partnership or any other person or entity
      controlled by, controlling or under common control with Maker. A person or
      entity of any nature shall be presumed to have control when it possesses
      the power, directly or indirectly, to direct, or cause the direction of,
      the management or policies of another person or entity, whether through
      ownership of voting securities, by contract, or otherwise.

            19. Severability. If any provision hereof or of any other document
securing or related to the indebtedness evidenced hereby is, for any reason and
to any extent, invalid or unenforceable, then neither the remainder of the
document in which such provision is contained, nor the application of the
provision to other persons, entities, or circumstances, nor any other document
referred to herein, shall be affected thereby, but instead shall be enforceable
to the maximum extent permitted by law.

            20. Transfer of Note. Each provision of this Note shall be and
remain in full force and effect notwithstanding any negotiation or transfer
hereof and any interest herein to any other Holder or participant.

            21. Governing Law. Regardless of the place of its execution, this
Note shall be construed and enforced in accordance with the laws of the
Commonwealth of Massachusetts.

            22. Time of Essence. Time is of the essence with respect to Maker's
obligations under this Note.

            23. Remedies Cumulative. The remedies provided to Holder in this
Note, the Mortgage and the other Loan Documents are cumulative and concurrent
and may be exercised singly, successively or together against Maker, the
Property, and other security, or any guarantor of this Note, at the sole and
absolute discretion of the Holder.

            24. No Waiver. Holder shall not by any act or omission be deemed to
waive any of its rights or remedies hereunder unless such waiver is in writing
and signed by the Holder and then only to the extent specifically set forth
therein. A waiver of one event shall not be construed as continuing or as a bar
to or waiver of any right or remedy granted to Holder hereunder in connection
with a subsequent event.

            25. Joint and Several Obligation. If Maker is more than one person
or entity, then (a) all persons or entities comprising Maker are jointly and
severally liable for all of the Maker's obligations hereunder; (b) all
representations, warranties, and covenants made by Maker shall be deemed
representations, warranties, and covenants of each of the persons or entities
comprising Maker; (c) any breach, Default or Event of Default by any of the
persons or entities comprising Maker hereunder shall be deemed to be a breach,
Default, or Event of Default of Maker; and (d) any reference herein contained to
the knowledge or awareness of Maker shall mean the knowledge or awareness of any
of the persons or entities comprising Maker.

                                       12
<PAGE>

            26. WAIVER OF JURY TRIAL. MAKER AND HOLDER KNOWINGLY, IRREVOCABLY,
VOLUNTARILY AND INTENTIONALLY WAIVE ANY RIGHT EITHER MAY HAVE TO A TRIAL BY JURY
IN RESPECT OF ANY ACTION, PROCEEDING OR COUNTERCLAIM BASED ON THIS NOTE, OR
ARISING OUT OF, UNDER OR IN CONNECTION WITH THIS NOTE, THE MORTGAGE, OR ANY
OTHER LOAN DOCUMENTS OR ANY COURSE OF CONDUCT, COURSE OF DEALING, STATEMENT
(WHETHER VERBAL OR WRITTEN) OR ACTIONS OF ANY PARTY HERETO OR TO ANY LOAN
DOCUMENT. THIS PROVISION IS A MATERIAL INDUCEMENT FOR MAKER AND HOLDER TO ENTER
INTO THE LOAN TRANSACTION EVIDENCED BY THIS NOTE.

            27. WAIVER OF PREPAYMENT RIGHT WITHOUT PREMIUM MAKER HEREBY
EXPRESSLY WAIVES ANY RIGHT IT MAY HAVE UNDER APPLICABLE LAW TO PREPAY THIS NOTE,
IN WHOLE OR IN PART, WITHOUT PREPAYMENT PREMIUM, UPON ACCELERATION OF THE
MATURITY DATE OF THIS NOTE, AND AGREES THAT, IF FOR ANY REASON A PREPAYMENT OF
ALL OR ANY PART OF THIS NOTE IS MADE, WHETHER VOLUNTARILY OR FOLLOWING ANY
ACCELERATION OF THE MATURITY DATE OF THIS NOTE BY HOLDER ON ACCOUNT OF THE
OCCURRENCE OF ANY EVENT OF DEFAULT ARISING FOR ANY REASON, INCLUDING, WITHOUT
LIMITATION, AS A RESULT OF ANY PROHIBITED OR RESTRICTED TRANSFER, FURTHER
ENCUMBRANCE OR DISPOSITION OF THE PROPERTY OR ANY PART THEREOF SECURING THIS
NOTE, THEN, EXCEPT AS OTHERWISE SET FORTH IN THIS NOTE OR THE OTHER LOAN
DOCUMENTS, MAKER SHALL BE OBLIGATED TO PAY, CONCURRENTLY WITH SUCH PREPAYMENT,
THE PREPAYMENT PREMIUM PROVIDED FOR IN THIS NOTE. MAKER HEREBY DECLARES THAT
HOLDER'S AGREEMENT TO MAKE THE LOAN AT THE INTEREST RATE AND FOR THE TERM SET
FORTH IN THIS NOTE CONSTITUTES ADEQUATE CONSIDERATION, GIVEN INDIVIDUAL WEIGHT
BY MAKER, FOR THIS WAIVER AND AGREEMENT.

                   [BALANCE OF PAGE INTENTIONALLY LEFT BLANK]

                                       13
<PAGE>

            IN WITNESS WHEREOF and intending to be legally bound, Maker has duly
executed this Note under seal as of the date first above written.

                                 MAKER:

                                 KS PARCEL D, LLC, a Delaware limited liability
                                 company

                                 By: Kendall Square, LLC, a Delaware limited
                                     liability company, its manager

                                     By: Lyme Properties LLC, a New Hampshire
                                         limited liability company, its manager

                                         By: /s/ David E. Clem
                                             -----------------------------------
                                         Name: David E. Clem
                                         Title: Manager<PAGE>
                                                                    Exhibit 10.8

COMMONWEALTH OF MASSACHUSETTS
COUNTY OF MIDDLESEX

Recording requested by:

And when recorded mail to:

Otten, Johnson, Robinson,
   Neff & Ragonetti, P.C.
950 Seventeenth Street
Suite 1600
Denver, Colorado 80202

Attention: Mark F. Copertino, Esq.

                  MORTGAGE, SECURITY AGREEMENT, FIXTURE FILING,
                              FINANCING STATEMENT
                       AND ASSIGNMENT OF LEASES AND RENTS
                            (WITH LEASEHOLD ADDENDUM)

         THIS MORTGAGE, SECURITY AGREEMENT, FIXTURE FILING, FINANCING STATEMENT
AND ASSIGNMENT OF LEASES AND RENTS (this "Mortgage") is executed as of November
21, 2003, by KS PARCEL D, LLC, a Delaware limited liability company
("Mortgagor"), in favor of, and for the use and benefit of, THE VARIABLE ANNUITY
LIFE INSURANCE COMPANY, a Texas corporation ("Mortgagee").

                                    ARTICLE 1
                       PARTIES, PROPERTY, AND DEFINITIONS

         The following terms and references shall have the meanings indicated:

         1.1 CHATTELS: All goods, fixtures, inventory, equipment, building and
other materials, supplies, and other tangible personal property of every nature,
whether now owned or hereafter acquired by Mortgagor, used, intended for use, or
reasonably required in the construction, development, or operation of the
Property, together with all accessions thereto, replacements and substitutions
therefor, and proceeds thereof.

         1.2 DEFAULT: Any matter which, with the giving of notice, passage of
time, or both, would constitute an Event of Default.

         1.3 ENVIRONMENTAL INDEMNITY AGREEMENT: The Environmental Indemnity
Agreement of even date herewith made by Mortgagor and Guarantor for the benefit
of Mortgagee.

<PAGE>

         1.4 ERISA: The Employee Retirement Income Security Act of 1974, as
amended, together with all rules and regulations issued thereunder.

         1.5 EVENT OF DEFAULT: As defined in ARTICLE 6.

         1.6 GENZYME: Genzyme Corporation, a Massachusetts corporation.

         1.7 GENZYME LEASE: The Lease dated as of August 28, 2000 between
Kendall Square, LLC, a Delaware limited liability company ("Kendall Square"),
and Genzyme, as assigned by Kendall Square to KS Parcel A/D, LLC, a Delaware
limited liability company, pursuant to an Assignment of Leases, Contracts and
Warranties and Permits dated as of July 17, 2002, as assigned by KS Parcel A,
LLC, a Delaware limited liability company (f/k/a KS Parcel A/D, LLC), to
Mortgagor pursuant to an Assignment of Leases, Contracts and Warranties and
Permits dated as of November 27, 2002, as amended by First Amendment to Lease
dated as of August 1, 2003, and as further amended from time to time.

         1.8 GUARANTOR: The Lyme Timber Company, a New Hampshire limited
partnership.

         1.9 GUARANTY AGREEMENT: The Guaranty Agreement of even date herewith
made by Guarantor for the benefit of Mortgagee.

         1.10 INSURANCE AGREEMENT: The Agreement Concerning Insurance
Requirements of even date herewith executed by Mortgagor for the benefit of
Mortgagee.

         1.11 INTANGIBLE PERSONALTY: The right to use all trademarks and trade
names and symbols or logos used in connection therewith, or any modifications or
variations thereof, in connection with the operation of the improvements
existing or to be constructed on the Property to the extent now owned or
hereafter acquired by Mortgagor, together with all accounts, deposit accounts,
letter of credit rights, investment property, monies in the possession of
Mortgagee (including without limitation proceeds from insurance, retainages and
deposits for taxes and insurance),, Permits, contract rights (including, without
limitation, rights to receive insurance proceeds) and general intangibles
(whether now owned or hereafter acquired, and including proceeds thereof)
relating to or arising from Mortgagor's ownership, use, operation, leasing, or
sale of all or any part of the Property, specifically including but in no way
limited to any right which Mortgagor may have or acquire to transfer any
development rights from the Property to other real property, and any development
rights which may be so transferred.

         1.12 LEASE CERTIFICATE: The certificate of even date herewith made by
Mortgagor to Mortgagee concerning Leases.

         1.13 LEASES: Any and all leases, subleases and other agreements,
including, without limitation, the Genzyme Lease, under the terms of which any
person other than Mortgagor has or acquires any right to occupy or use the
Property, or any part thereof.

         1.14 LOAN: The loan from Mortgagee to Mortgagor evidenced by the Note.

                                       2
<PAGE>

         1.15 LOAN DOCUMENTS: The Note, all of the deeds of trust, mortgages and
other instruments and documents securing or executed and delivered in connection
with the Note, including this Mortgage, the Insurance Agreement, the
Environmental Indemnity Agreement, the Guaranty Agreement, the Lease Certificate
and each other document executed or delivered in connection with the transaction
pursuant to which the Note has been executed and delivered. The term "Loan
Documents" also includes all modifications, extensions, renewals, and
replacements of each document referred to above.

         1.16 MORTGAGEE: The Mortgagee named in the introductory paragraph of
this Mortgage, whose legal address is c/o AIG Global Investment Corp., 1
SunAmerica Center, Century City, Los Angeles, California 90067-6022, together
with any future holder of the Note.

         1.17 MORTGAGOR: The Mortgagor named in the introductory paragraph of
this Mortgage (Taxpayer Identification No. 02-0519064; Organizational I.D. No.
3564429), whose legal address is 101 Main Street, 18th Floor, Cambridge,
Massachusetts 02142, together with any future owner of the Property or any part
thereof or interest therein.

         1.18 NOTE: Mortgagor's promissory note of even date herewith, payable
to the order of Mortgagee in the principal face amount of $75,000,000.00, the
last payment under which is due on December 1, 2018, or, if extended by
Mortgagee pursuant to its terms, December 1, 2023, unless such due date is
accelerated, together with all renewals, extensions and modifications of such
promissory note. All terms and provisions of the Note are incorporated by this
reference in this Mortgage.

         1.19 PERMITS: All permits, licenses, certificates and authorizations
necessary for the beneficial development, ownership, use, occupancy, operation
and maintenance of the Property (other than any required to be obtained by any
tenant(s) of the Property).

         1.20 PERMITTED EXCEPTIONS: The matters (excluding matters of survey)
set forth in Schedule B-I of the title insurance policy insuring the lien
created by this Mortgage, in form and substance satisfactory to, and accepted
by, Mortgagee, that Mortgagor has caused to be delivered to Mortgagee in
connection with the Loan.

         1.21 PROPERTY: The tract or tracts of land described in Exhibit A
attached, together with the following:

                  (a) All buildings, structures, and improvements now or
hereafter located on such tract or tracts, as well as all rights-of-way,
easements, and other appurtenances thereto;

                  (b) All of Mortgagor's right, title and interest in and to any
land lying between the boundaries of such tract or tracts and the center line of
any adjacent street, road, avenue, or alley, whether opened or proposed whether
now owned or hereafter acquired by Mortgagor;

                  (c) All of the rents, income, receipts, revenues, issues and
profits of and from such tract or tracts and improvements;

                                       3
<PAGE>

                  (d) All (i) water and water rights (whether decreed or
undecreed, tributary, nontributary or not nontributary, surface or underground,
or appropriated or unappropriated); (ii) ditches and ditch rights; (iii) spring
and spring rights; (iv) reservoir and reservoir rights; and (v) shares of stock
in water, ditch and canal companies and all other evidence of such rights, which
are now owned or hereafter acquired by Mortgagor and which are appurtenant to or
which have been used in connection with such tract or tracts or improvements;

                  (e) All minerals, crops, timber, trees, shrubs, flowers, and
landscaping features now or hereafter located on, under or above such tract or
tracts;

                  (f) All machinery, apparatus, equipment, fittings, fixtures
(whether actually or constructively attached, and including all trade, domestic,
and ornamental fixtures, but excluding any such items owned by tenants under
Leases) now owned or hereafter acquired by Mortgagor and now or hereafter
located in, upon, or under such tract or tracts or improvements and used or
usable in connection with any present or future operation thereof, including but
not limited to all heating, air-conditioning, freezing, lighting, laundry,
incinerating and power equipment; engines; pipes; pumps; tanks; motors;
conduits; switchboards; plumbing, lifting, cleaning, fire prevention, fire
extinguishing, refrigerating, ventilating, cooking, and communications
apparatus; boilers, water heaters, ranges, furnaces, and burners; appliances;
vacuum cleaning systems; elevators; escalators; shades; awnings; screens; storm
doors and windows; stoves; refrigerators; attached cabinets; partitions; ducts
and compressors; rugs and carpets; draperies; and all additions thereto and
replacements therefor;

                  (g) All development rights associated with such tract or
tracts, whether previously or subsequently transferred to such tract or tracts
from other real property or now or hereafter susceptible of transfer from such
tract or tracts to other real property;

                  (h) All awards and payments, including interest thereon,
resulting from the exercise of any right of eminent domain or any other public
or private taking of, injury to, or decrease in the value of, any of such
property, but excluding any such awards or payments properly due and payable to
tenants under Leases; and

                  (i) All other and greater rights and interests of every nature
in such tract or tracts and in the possession or use thereof and income
therefrom, whether now owned or subsequently acquired by Mortgagor.

         1.22 SECURED OBLIGATIONS: All present and future obligations of
Mortgagor to Mortgagee evidenced by or contained in the Note, the Environmental
Indemnity Agreement, this Mortgage and all other Loan Documents, whether stated
in the form of promises, covenants, representations, warranties, conditions, or
prohibitions or in any other form. If the maturity of the Note secured by this
Mortgage is accelerated, the Secured Obligations shall include an amount equal
to any prepayment premium which would be payable under the terms of the Note as
if the Note were voluntarily prepaid in full on the date of the acceleration.

         1.23 SERVICER. Mortgagee's servicer for the Loan, as designated by
Mortgagee from lime to time.

                                       4
<PAGE>

                                    ARTICLE 2
                                GRANTING CLAUSE

         2.1 GRANT TO MORTGAGEE. As security for the Secured Obligations,
Mortgagor hereby grants, bargains, sells, conveys, mortgages, and warrants with
MORTGAGE COVENANTS unto Mortgagee the entire right, title, interest, and estate
of Mortgagor in and to the Property, whether now owned or hereafter acquired; TO
HAVE AND TO HOLD the same, together with all and singular the rights,
hereditaments, and appurtenances in anywise appertaining or belonging thereto,
unto Mortgagee and Mortgagee's successors, substitutes and assigns forever.

         2.2 SECURITY INTEREST TO MORTGAGEE. As additional security for the
Secured Obligations, Mortgagor hereby grants to Mortgagee a security interest in
the Property, Chattels and Intangible Personalty. To the extent any of the
Property, Chattels or the Intangible Personalty may be or have been acquired
with funds advanced by Mortgagee under the Loan Documents, this security
interest is a purchase money security interest. This Mortgage constitutes a
Security Agreement under the Uniform Commercial Code of the state in which the
Property is located (the "Code") with respect to any part of the Property,
Chattels and Intangible Personalty that may or might now or hereafter be or be
deemed to be personal property, fixtures or property other than real estate (all
collectively hereinafter called "Collateral"); all of the terms, provisions,
conditions and agreements contained in this Mortgage pertain and apply to the
Collateral as fully and to the same extent as to any other property comprising
the Property, and the following provisions of this Section shall not limit the
generality or applicability of any other provisions of this Mortgage but shall
be in addition thereto:

                  (a) The Collateral shall be used by Mortgagor solely for
business purposes, and all Collateral (ether than the Intangible Personalty)
shall be installed upon the real estate comprising part of the Property for
Mortgagor's own use or as the equipment and furnishings famished by Mortgagor,
as landlord, to tenants of the Property;

                  (b) The Collateral (other than the Intangible Personalty)
shall be kept at the real estate comprising a part of the Property, and shall
not, subject to SECTION 5.7, be removed therefrom without the consent of
Mortgagee (being the Secured Party as that term is used in the Code); and the
Collateral (other than the Intangible Personalty) may be affixed to such real
estate but shall not be affixed to any other real estate;

                  (c) No financing statement covering any of the Collateral or
any proceeds thereof is on file in any public office; and Mortgagor will, at
its cost and expense, upon demand, furnish to Mortgagee such further information
and will execute and deliver to Mortgagee such financing statements and other
documents in form satisfactory to Mortgagee and will do all such acts and things
as Mortgagee may at any time or from time to time reasonably request or as may
be necessary or appropriate to establish and maintain a perfected first-priority
security interest in the Collateral as security for the Secured Obligations,
subject to no adverse liens or encumbrances; and Mortgagor will pay the cost of
filing the same or filing or recording such financing statements or other
documents and this instrument in all public offices wherever filing or recording
is deemed by Mortgagee to be necessary or desirable;

                                       5
<PAGE>

                  (d) The terms and provisions contained in this Section and in
SECTION 7.6 of this Mortgage shall, unless the context otherwise requires, have
the meanings and be construed as provided in the Code; and

                  (e) This Mortgage constitutes a financing statement under the
Code with respect to the Collateral. As such, this Mortgage covers all items of
the Collateral that are or are to become fixtures. The filing of this Mortgage
in the real estate records of the county where the Property is located shall
constitute a fixture filing in accordance with the Code. Information concerning
the security interests created hereby may be obtained at the addresses set forth
in ARTICLE 1 of this Mortgage. Mortgagor is the "Debtor" and Mortgagee is the
"Secured Party" (as those terms are defined and used in the Code) insofar as
this Mortgage constitutes a financing statement.

                                    ARTICLE 3
                   MORTGAGOR'S REPRESENTATIONS AND WARRANTIES

         3.1 WARRANTY OF TITLE. Mortgagor represents and warrants to Mortgagee
that:

                  (a) Mortgagor has good and marketable fee simple title to the
Property, and such fee simple title is free and clear of all liens,
encumbrances, security interests and other claims whatsoever, subject only to
the Permitted Exceptions;

                  (b) Mortgagor is the sole and absolute owner of the Chattels
and the Intangible Personalty, free and clear of all liens, encumbrances,
security interests and other claims whatsoever, subject only to the Permitted
Exceptions;

                  (c) This Mortgage is a valid and enforceable first lien and
security interest on the Property, Chattels and Intangible Personalty, subject
only to the Permitted Exceptions;

                  (d) Mortgagor, for itself and its successors and assigns,
hereby agrees to warrant and forever defend, all and singular of the property
and property interests granted and conveyed pursuant to this Mortgage, against
every person whomsoever lawfully claiming, or to claim, the same or any part
thereof; and

         The representations, warranties and covenants contained in this Section
shall survive foreclosure of this Mortgage, and shall inure to the benefit of
and be enforceable by any person who may acquire title to the Property, the
Chattels, or the Intangible Personalty pursuant to any such foreclosure.

         3.2 DUE AUTHORIZATION. If Mortgagor is other than a natural person,
then each individual who executes this document on behalf of Mortgagor
represents and warrants to Mortgagee that such execution has been duly
authorized by all necessary corporate, partnership, limited liability company or
other action on the part of Mortgagor. Mortgagor represents that Mortgagor has
obtained all consents and approvals required in connection with the execution,
delivery and performance of this Mortgage by Mortgagor;

                                       6
<PAGE>

         3.3 OTHER REPRESENTATIONS AND WARRANTIES. Mortgagor represents and
warrants to Mortgagee as follows:

                  (a) Mortgagor is a limited liability company, duly organized,
validly existing and in good standing under the laws of the State of Delaware.
Mortgagor is duly authorized to transact business in and is in good standing
under the laws of the Commonwealth of Massachusetts. Guarantor is a limited
partnership, duly organized, validly existing and in good standing under the
laws of the State of New Hampshire, and is duly authorized to transact business
in and is in good standing under the laws of the Commonwealth of Massachusetts
and is the sole member of Lyme Properties LLC, which is the sole manager of
Kendall Square, LLC, which is the sole member and manager of Mortgagor;

                  (b) The execution, delivery and performance by Mortgagor of
the Loan Documents are within Mortgagor's power and authority and have been duly
authorized by all necessary action;

                  (c) This Mortgage is, and each other Loan Document to which
Mortgagor or Guarantor is a party will, when delivered hereunder, be valid and
binding obligations of Mortgagor and Guarantor enforceable against Mortgagor and
Guarantor in accordance with their respective terms, except as limited by
equitable principles and bankruptcy, insolvency and similar laws affecting
creditors' rights;

                  (d) The execution, delivery and performance by Mortgagor and
Guarantor of the Loan Documents will not contravene any contractual or other
restriction binding on or affecting Mortgagor or Guarantor and will not result
in or require the creation of any lien, security interest, other charge or
encumbrance (other than pursuant hereto) upon or with respect to any of its
properties;

                  (e) The execution, delivery and performance by Mortgagor and
Guarantor of the Loan Documents does not contravene any applicable law;

                  (f) No authorization, approval, consent or other action by,
and no notice to or filing with, any court, governmental authority or regulatory
body is required for the due execution, delivery and performance by Mortgagor
and Guarantor of any of the Loan Documents or the effectiveness of any
assignment of any of Mortgagor's rights and interests of any kind to Mortgagee;

                  (g) No part of the Property, Chattels, or Intangible
Personalty is in the hands of a receiver, no application for a receiver is
pending with respect to any portion of the Property, Chattels, or Intangible
Personalty, and no part of the Property, Chattels, or Intangible Personalty is
subject to any foreclosure or similar proceeding;

                  (h) Neither Mortgagor nor Guarantor has made any assignment
for the benefit of creditors, nor has Mortgagor or Guarantor filed, or had
filed against it, any petition in bankruptcy;

                  (i) Except as has been disclosed in writing by Mortgagor to
Mortgagee, there is no pending or, to the best of Mortgagor's knowledge,
threatened, litigation,

                                       7
<PAGE>

action, proceeding or investigation, including, without limitation, any
condemnation proceeding, against Mortgagor or the Property before any court,
governmental or quasi-governmental, arbitrator or other authority. There is no
pending or, to the best of Mortgagor's knowledge, threatened, litigation,
action, proceeding or investigation against Guarantor before any court,
governmental or quasi-governmental, arbitrator or other authority which, if
determined adversely, would have a material adverse effect on Guarantor's
ability to perform its obligations under the Loan Documents;

                  (j) Mortgagor is a "non-foreign person" within the meaning of
Sections 1445 and 7701 of the United States Internal Revenue Code of 1986, as
amended, and the regulations issued thereunder;

                  (k) Access to and egress from the Property are available and
provided by public streets (or by private way connecting to such public streets
pursuant to rights of record), and Mortgagor has no knowledge of any federal,
state, county, municipal or other governmental plans to change the highway or
road system in the vicinity of the Property or to restrict or change access from
any such highway or road to the Property;

                  (l) All public utility services necessary for the operation of
all improvements constituting part of the Property for their intended purposes
are available at the boundaries of the land constituting part of the Property,
including water supply, storm and sanitary sewer facilities, and natural gas,
electric and telephone;

                  (m) The Property is located in a zoning district designated
Planned Unit Development District 3, by the City of Cambridge, Massachusetts.
Such designation permits the development, use and operation of the Property as
it is currently operated as a permitted, and not as a non-conforming use. The
Property complies in all respects with all zoning ordinances, regulations,
requirements, conditions and restrictions, including but not limited to deed
restrictions and restrictive covenants, applicable to the Property;

                  (n) There are no special or other assessments for public
improvements or otherwise now affecting the Property, nor does Mortgagor know of
any pending or threatened special assessments affecting the Property or any
contemplated improvements affecting the Property that may result in special
assessments. There are no tax abatements or exceptions affecting the Property;

                  (o) Mortgagor and Guarantor have filed all tax returns they
are required to have filed, and have paid all taxes as shown on such returns or
on any assessment received pertaining to the Property;

                  (p) Mortgagor has not received any notice from any
governmental body having jurisdiction over the Property as to any violation of
any applicable law, or any notice from any insurance company or inspection or
rating bureau setting forth any requirements as a condition to the continuation
of any insurance coverage on or with respect to the Property or the continuation
thereof at premium rates existing at present which have not been remedied or
satisfied;

                                       8
<PAGE>

                  (q) Mortgagor is not in default, in any manner which would
materially adversely affect its properties, assets, operations or condition
(financial or otherwise), in the performance, observance or fulfillment of any
of the obligations, covenants or conditions set forth in any agreement or
instrument to which it is a party or by which it or any of its properties,
assets or revenues are bound. Guarantor is not in default, in any manner which
would materially adversely affect its ability to perform its obligations under
the Loan Documents, in the performance, observance or fulfillment of any of the
obligations, covenants or conditions set forth in any agreement or instrument to
which it is a party or by which it or any of its properties, assets or revenues
are bound;

                  (r) Except as set forth in the Lease Certificate, there are no
occupancy rights (written or oral), Leases or tenancies presently affecting any
part of the Property. The Lease Certificate contains a true and correct
description of all Leases presently affecting the Property. No written or oral
agreements or understandings exist between Mortgagor and the tenants under the
Leases described in the Lease Certificate that grant such tenants any rights
greater than those described in the Leases listed in the Lease Certificate or
that are in any way inconsistent with the rights described in the Leases listed
in the Lease Certificate;

                  (s) There are no purchase options, purchase contracts or other
similar agreements of any type (written or oral) presently affecting any part of
the Property;

                  (t) There exists no brokerage agreement with respect to any
part of the Property, other than a brokerage agreement relating to the placement
of Loan;

                  (u) Except as otherwise disclosed to Mortgagee in writing
prior to the date hereof, (i) there are no contracts presently affecting the
Property ("Contracts") having a term in excess of one hundred eighty (180) days
or not terminable by Mortgagor (without penalty) on thirty (30) days' notice,
except as listed in Exhibit B attached hereto; (ii) Mortgagor has heretofore
delivered to Mortgagee true and correct copies of each of the Contracts together
with all amendments thereto; (iii) Mortgagor is not in default of any
obligations under any of the Contracts; and (iv) the Contracts represent the
complete agreement between Mortgagor and such other parties as to the services
to be performed or materials to be provided thereunder and the compensation to
be paid for such services or materials, as applicable, and except as otherwise
disclosed herein, such other parties possess no unsatisfied claims against
Mortgagor. Mortgagor is not in default under any of the Contracts and no event
has occurred which, with the passing of time or the giving of notice, or both,
would constitute a default by Mortgagor under any of the Contracts;

                  (v) Mortgagor has obtained all Permits necessary for the
operation, use, ownership, development, occupancy and maintenance of the
Property as a research laboratory and office building, as it is currently being
operated. None of the Permits has been suspended or revoked, and all of the
Permits are in full force and effect, are fully paid for, and Mortgagor has made
or will make application for renewals of any of the Permits prior to the
expiration thereof;

                  (w) All insurance policies held by Mortgagor relating to or
affecting the Property are in fall force and effect and all policies of
insurance required under the Loan

                                       9
<PAGE>

Documents shall remain in full force and effect until all Secured Obligations
are satisfied. Mortgagor has not received any notice of default or notice
terminating or threatening to terminate any such insurance policies. Mortgagor
has made or will make application for renewals of any of such insurance policies
prior to the expiration thereof;

                  (x) Mortgagor currently complies with ERISA. Neither the
making of the Loan and secured by this Mortgage nor the exercise by Mortgagee of
any of its rights under the Loan Documents constitutes or will constitute a
non-exempt, prohibited transaction under ERISA: and

                  (y) Mortgagor's exact legal name is correctly set out in the
introductory paragraph of this Mortgage. Mortgagor's organizational
identification number is correctly set forth in the definition of "Mortgagor"
set forth in ARTICLE 1 hereof. Mortgagor's location (as such term is used in
SECTION 5.8 hereof) is the State of Delaware.

         3.4 CONTINUING EFFECT. Mortgagor shall be liable to Mortgagee for any
damage suffered by Mortgagee if any of the foregoing representations are
inaccurate as of the date hereof, regardless of when such inaccuracy may be
discovered by, or result in harm to, Mortgagee. Mortgagor further represents and
warrants that the foregoing representations and warranties, as well as all other
representations and warranties of Mortgagor to Mortgagee relative to the Loan
Documents, shall remain true and correct during the term of the Note and shall
survive termination of this Mortgage.

                                    ARTICLE 4
                        MORTGAGOR'S AFFIRMATIVE COVENANTS

         4.1 PAYMENT OF NOTE. Mortgagor will pay all principal, interest, and
other sums payable under the Note, on the date when such payments are due,
without notice or demand.

         4.2 PERFORMANCE OF OTHER OBLIGATIONS. Mortgagor will promptly and
strictly perform and comply with all other covenants, conditions, and
prohibitions required of Mortgagor by the terms of the Loan Documents.

         4.3 OTHER ENCUMBRANCES. Mortgagor will promptly perform and comply with
all covenants, conditions, and prohibitions required of Mortgagor in connection
with any other encumbrance affecting the Property, the Chattels, or the
Intangible Personalty, or any part thereof, or any interest therein, regardless
of whether such other encumbrance is superior or subordinate to the lien hereof.

         4.4 PAYMENT OF TAXES.

                  (a) Property Taxes. Unless Mortgagor is depositing money into
escrow pursuant to SECTION 4.4(b), Mortgagor will (i) pay, before delinquency,
all taxes and assessments, general or special, which may be levied or imposed at
any time against Mortgagor's interest and estate in the Property, the Chattels,
or the Intangible Personalty, and (ii) within ten days after each payment of any
such tax or assessment, Mortgagor will deliver to Mortgagee, without notice or
demand, an official receipt for such payment. At Mortgagee's option,

                                       10
<PAGE>

Mortgagee may retain the services of a firm to monitor the payment of all taxes
and assessments relating to the Property, the cost of which shall be borne by
Mortgagor.

                  (b) Deposit for Taxes. Upon Mortgagee's demand following the
occurrence of any Default, Event of Default, failure by Mortgagor or Genzyme to
timely make any required payment of taxes, or any termination of the Genzyme
Lease, Mortgagor shall deposit with Mortgagee an amount equal to 1/12th of the
amount which Mortgagee estimates will be required to make the next annual
payment of taxes, assessments, and similar governmental charges referred to in
this Section, multiplied by the number of whole or partial months that have
elapsed since the date one month prior to the most recent due date for such
taxes, assessments and similar governmental charges. Thereafter, with each
monthly payment under the Note, Mortgagor shall deposit with Mortgagee an amount
equal to 1/12th of the amount which Mortgagee estimates will be required to pay
the next annual payment of taxes, assessments, and similar governmental charges
referred to in this Section. The purpose of these provisions is to provide
Mortgagee with sufficient funds on hand to pay all such taxes, assessments, and
other governmental charges thirty (30) days before the date on which they become
past due. If the Mortgagee, in its sole discretion, determines that the funds
escrowed hereunder are, or will be, insufficient, Mortgagor shall upon demand
pay such additional sums as Mortgagee shall determine necessary and shall pay
any increased monthly charges requested by Mortgagee. Provided no Default or
Event of Default exists hereunder, Mortgagee will apply the amounts so deposited
to the payment of such taxes, assessments, and other charges when due, and any
amount so deposited may be held and commingled with Mortgagee's own funds.
Provided that Mortgagor pays the expenses incurred by Mortgagee's loan servicer
in establishing and maintaining such an account, the amounts deposited hereunder
shall be deposited into an interest bearing account for Mortgagor's benefit.

                  (c) Intangible Taxes. If by reason of any statutory or
constitutional amendment or judicial decision adopted or rendered after the date
hereof, any tax, assessment, or similar charge is imposed against the Note,
Mortgagee, or any interest of Mortgagee in any real or personal property
encumbered hereby, Mortgagor will pay such tax, assessment, or other charge
before delinquency and will indemnify Mortgagee against all loss, expense, or
diminution of income in connection therewith. In the event Mortgagor is unable
to do so, either for economic reasons or because the legal provisions or
decisions creating such tax, assessment or charge forbid Mortgagor from doing
so, then the Note will, at Mortgagee's option, become due and payable in full
upon thirty (30) days' notice to Mortgagor.

                  (d) Right to Contest. Notwithstanding any other provision of
this Section, Mortgagor will not be deemed to be in default (and no deposit
shall be required under SECTION 4.4(b) above) solely by reason of Mortgagor's
failure to pay any tax, assessment or similar governmental charge so long as, in
Mortgagee's judgment, each of the following conditions is satisfied:

                           (i) Mortgagor is engaged in and diligently pursuing
         in good faith administrative or judicial proceedings appropriate to
         contest the validity or amount of such tax, assessment, or charge; and

                                       11
<PAGE>

                           (ii) Mortgagor's payment of such tax, assessment, or
         charge would necessarily and materially prejudice Mortgagor's prospects
         for success in such proceedings; and

                           (iii) Nonpayment of such tax, assessment, or charge
         will not result in the loss or forfeiture of any property encumbered
         hereby or any interest of Mortgagee therein; and

                           (iv) Mortgagor deposits with Mortgagee, as security
         for such payment which may ultimately be required, a sum equal to the
         amount of the disputed tax, assessment or charge plus the interest,
         penalties, advertising charges, and other costs which Mortgagee
         estimates are likely to become payable if Mortgagor's contest is
         unsuccessful.

If Mortgagee determines that any one or more of such conditions is not satisfied
or is no longer satisfied, Mortgagor will pay the tax, assessment, or charge in
question, together with any interest and penalties thereon, within ten (10) days
after Mortgagee gives notice of such determination.

         4.5 MAINTENANCE OF INSURANCE.

                  (a) Coverages Required. Mortgagor shall maintain or cause to
be maintained, with financially sound and reputable insurance companies or
associations satisfactory to Mortgagee, all insurance required under the terms
of the Insurance Agreement, and shall comply with each and every covenant and
agreement contained in the Insurance Agreement.

                  (b) Renewal Policies. Not less than thirty (30) days prior to
the expiration date of each insurance policy required pursuant to the Insurance
Agreement, Mortgagor will deliver to Mortgagee an appropriate renewal policy (or
a certified copy thereof), together with evidence satisfactory to Mortgagee that
the applicable premium has been prepaid.

                  (c) Deposit for Premiums. Upon Mortgagee's demand following
the occurrence of any Default, Event of Default, failure by Mortgagor or Genzyme
to timely make any required payment of insurance premiums or any termination of
the Genzyme Lease, Mortgagor shall deposit with Mortgagee an amount equal to
1/12th of the amount which Mortgagee estimates will be required to make the next
annual payments of the premiums for the policies of insurance referred to in
this Section, multiplied by the number of whole and partial months which have
elapsed since the date one month prior to the most recent policy anniversary
date for each such policy. Thereafter, with each monthly payment under the Note,
Mortgagor will deposit an amount equal to l/12th of the amount which Mortgagee
estimates will be required to pay the next required annual premium for each
insurance policy referred to in this Section. The purpose of these provisions is
to provide Mortgagee with sufficient funds on hand to pay all such premiums
thirty (30) days before the date on which they become past due. If the
Mortgagee, in its sole discretion, determines that the funds escrowed hereunder
are, or will be, insufficient, Mortgager shall upon demand pay such additional
sums as Mortgagee shall determine necessary and shall pay any increased monthly
charges requested by Mortgagee.

                                       12
<PAGE>

Provided no Default or Event of Default exists hereunder, Mortgagee will apply
the amounts so deposited to the payment of such insurance premiums when due and
the money so received may be held and commingled with Mortgagee's own funds.
Provided that Mortgagor pays the expenses incurred by Mortgagee's loan servicer
in establishing and maintaining such an account, the amounts deposited hereunder
shall be deposited into an interest bearing account for Mortgagor's benefit.

                  (d) Application of Hazard Insurance Proceeds. Mortgagor shall
promptly notify Mortgagee of any damage or casualty to all or any portion of the
Property or Chattels. Mortgagee may participate in all negotiations and appear
and participate in all judicial arbitration proceedings concerning any insurance
proceeds which may be payable as a result of such casualty or damage, and may,
in Mortgagee's sole discretion, compromise or settle, in the name of Mortgagee.
Mortgagor, or both any claim for any such insurance proceeds. Notwithstanding
the previous sentence, provided no Event of Default exists, Mortgagor shall have
the right to settle claims of not more than $500,000.00 without obtaining
Mortgagee's consent. Any such insurance proceeds shall be paid to Mortgagee and
shall be applied first to reimburse Mortgagee for all costs and expenses,
including attorneys' fees, incurred by Mortgagee in connection with the
collection of such insurance proceeds. The balance of any insurance proceeds
received by Mortgagee with respect to an insured casualty may, in Mortgagee's
sole discretion, either (i) be retained and applied by Mortgagee toward payment
of the Secured Obligations without application of any prepayment premium, or
(ii) be paid over, in whole or in part and subject to such conditions as
Mortgagee may impose, to Mortgagor to pay for repairs or replacements
necessitated by the casualty; provided, however, that if all of the Secured
Obligations have been performed or are discharged by the application of less
than all of such insurance proceeds, then any remaining proceeds will be paid
over to Mortgagor. Notwithstanding the preceding sentence, if (A) no Default or
Event of Default shall exist hereunder, (B) Mortgagor is obligated under the
terms of the Genzyme Lease to rebuild the property,, (C) Mortgagor can
demonstrate to Mortgagee's satisfaction that Mortgagor has the financial ability
to carry the Loan during reconstruction (from the proceeds of rent insurance or
otherwise), (D) such damage or destruction occurs prior to the last eighteen
months of the Loan, (E) such proceeds are released under escrow/construction
funding arrangements satisfactory to Mortgagee, (F) annual income from leases in
place and approved by Mortgagee (or not requiring Mortgagee's approval) that
will survive restoration provide coverage of at least 1.00 times the annual debt
service, and Mortgagor demonstrates to Mortgagee's reasonable satisfaction that
it will be able to attain coverage of at least 2.00 times the annual debt
service from leases approved by Mortgagee within six months after completion of
restoration, and (G) the repairs and/or restoration will return the improvements
to substantially the size, design and utility as existed immediately before the
casualty, then Mortgagee shall apply such proceeds in accordance with clause
(ii) above. Mortgagee may, prior to the application of insurance proceeds,
commingle them with Mortgagee's own funds and otherwise act with regard to such
proceeds as Mortgagee may determine in Mortgagee's sole discretion. If Mortgagee
applies such insurance proceeds in accordance with SECTION 4.5(d)(i), above,
Mortgagee shall reamortize the then-existing principal balance of the Loan over
the remaining portion of the Amortization Period or New Amortization Period, as
the case may be (as such terms are defined in the Note).

                                       13
<PAGE>

                  (e) Successor's Rights. Any person who acquires title to the
Property or the Chattels upon foreclosure hereunder will succeed to all of
Mortgagor's rights under all policies of insurance maintained pursuant to this
Section.

         4.6 MAINTENANCE AND REPAIR OF PROPERTY AND CHATTELS. Mortgagor will at
all times maintain the Property and the Chattels in good condition and repair,
will diligently prosecute the completion of any building or other improvement
which is at any time in the process of construction on the Property, and,
provided Mortgagee makes proceeds available therefor pursuant to SECTIONS 4.5 or
4.8, as applicable, will promptly repair, restore, replace, or rebuild any part
of the Property or the Chattels which may be affected by any casualty or any
public or private taking or injury to the Property or the Chattels. All costs
and expenses arising cut of tie foregoing shall be paid by Mortgagor whether or
not the proceeds of any insurance or eminent domain shall be sufficient
therefor. Mortgagor will comply with all statutes, ordinances, and other
governmental or quasi-governmental requirements and private covenants relating
to the ownership, construction, use, or operation of the Property, including but
not limited to any environmental or ecological requirements; provided, that so
long as Mortgagor is not otherwise in default hereunder, Mortgagor may, upon
providing Mortgagee with security reasonably satisfactory to Mortgagee, proceed
diligently and in good faith to contest the validity or applicability of any
such statute, ordinance, or requirement. Mortgagee and any person authorized by
Mortgagee may, upon prior written notice, enter and inspect the Property at all
reasonable times, and may inspect the Chattels, wherever located, at all
reasonable times.

         4.7 LEASES. Mortgagor shall timely pay and perform each of its
obligations under or in connection with the Leases, including, without
limitation, all obligations with respect to any repairs or reconstruction in the
event of a casualty or condemnation, and shall otherwise pay such sums and take
such action as shall be necessary or required in order to maintain each of the
Leases in full force and effect in accordance with its terms. Mortgagor shall
immediately furnish to Mortgagee copies of any notices given to Mortgagor by the
lessee under any Lease, alleging the default by Mortgagor in the timely payment
or performance of its obligations under such Lease and any subsequent
communication related thereto. Mortgagor agrees that, if Mortgagor shall fail to
do so, then Mortgagee, in its sole discretion, may advance any sum or take any
action which Mortgagee believes is necessary or required to cure the alleged
default or maintain the Leases in full force and effect, and all such sums
advanced by Mortgagee, together with all costs and expenses incurred by
Mortgagee in connection with action taken by Mortgagee pursuant to this Section,
shall be due and payable by Mortgagor to Mortgagee upon demand, shall bear
interest from the date that is ten (10) days following demand therefor until
paid at the Default Rale (as defined in the Note), and shall be secured by this
Mortgage.

         4.8 EMINENT DOMAIN; PRIVATE DAMAGE. If all or any part of the Property
is taken or damaged by eminent domain or any other public or private action,
Mortgagor will notify Mortgagee promptly of the time and place of all meetings,
hearings, trials, and other proceedings relating to such action. Mortgagee may
participate in all negotiations and appear and participate in all judicial or
arbitration proceedings concerning any award or which may be due as a result of
such taking or damage, and may, in Mortgagee's reasonable discretion, compromise
or settle, in the names of both Mortgagor and Mortgagee, any claim for any such
award or payment. Any such award or payment is to be paid to Mortgagee and will
be applied first to reimburse Mortgagee for all costs and expenses, including
attorneys' fees, incurred by Mortgagee in

                                       14
<PAGE>

connection with the ascertainment and collection of such award or payment. The
balance, if any, of such award or payment may, in Mortgagee's sole discretion,
either (a) be retained by Mortgagee and applied toward the Secured Obligations
without application or any prepayment premium, or (b) be paid over, in whole or
in part and subject to such conditions as Mortgagee may impose, to Mortgagor for
the purpose of restoring, repairing, or rebuilding any part of the Property
affected by the taking or damage. Notwithstanding the preceding sentence, if (i)
no Default or Event of Default shall exist hereunder, (ii) Mortgagor is
obligated under the terms of the Genzyme Lease to rebuild the property, (iii)
Mortgagor can demonstrate to Mortgagee's satisfaction that Mortgagor has the
financial ability to carry the Loan during reconstruction (from the proceeds of
rent insurance or otherwise), (iv) such damage or destruction occurs prior to
the last eighteen months of the Loan, (v) such proceeds are released under
escrow/construction funding arrangements satisfactory to Mortgagee, (vi) annual
income from leases in place and approved by Mortgagee (or not requiring
Mortgagee's approval) that will survive restoration provide coverage of at least
1.00 times the annual debt service, and Mortgagor demonstrates to Mortgagee's
reasonable satisfaction that it will be able to attain coverage of at least 2.00
times the annual debt service from leases approved by Mortgagee within six
months after completion of restorations and (vii)the repairs and/or restoration
will return the improvements to substantially the size, design and utility as
existed immediately before the casualty, then Mortgagee shall apply such
proceeds in accordance with clause (b) above. Mortgagor's duty to pay the Note
in accordance with its terms and to perform the other Secured Obligations will
not be suspended by the pendency or discharged by the conclusion of any
proceedings for the collection of any such award or payment, and any reduction
in the Secured Obligations resulting from Mortgagee's application of any such
award or payment will take effect only when Mortgagee receives such award or
payment. If this Mortgage has been foreclosed prior to Mortgagee's receipt of
such award or payment, Mortgagee may nonetheless retain such award or payment or
the extent required to reimburse Mortgagee for all costs and expenses, including
attorneys' fees, incurred in connection therewith, and to discharge any
deficiency remaining with respect to the Secured Obligations. If Mortgagee
applies such proceeds in accordance with SECTION 4.8(a), above. Mortgagee shall
reamortize the then-existing principal balance of the Loan over the remaining
portion of the Amortization Period or New Amortization Period, as the case may
be.

         4.9 MECHANICS' LIENS. Mortgagor will keep the Property free and clear
of all liens and claims of liens by contractors, subcontractors, mechanics,
laborers, materialmen, and other such persons, and will cause any recorded
statement of any such lien to be released of record within thirty (30) days
after the recording thereof. Notwithstanding the preceding sentence, however,
Mortgagor will not be deemed to be in default under this Section if and so long
as Mortgagor (a) contests in good faith the validity or amount of any asserted
lien and diligently prosecutes or defends an action appropriate to obtain a
binding determination of the disputed matter, (b) provides Mortgagee with such
security as Mortgagee may require to protect Mortgagee against all loss, damage,
and expense, including reasonable attorneys' fees, which Mortgagee might incur
if the asserted lien is determined to be valid.

         4.10 DEFENSE OF ACTIONS. Mortgagor will defend, at Mortgagor's expense,
any action, proceeding or claim which affects any property encumbered hereby or
any interest of Mortgagee in such property or in the Secured Obligations, and
will indemnify and hold

                                       15
<PAGE>

Mortgagee harmless from all loss, damage, cost, or expense, including reasonable
attorneys' fees, which Mortgagee may incur in connection therewith.

         4.11 EXPENSES OF ENFORCEMENT. Mortgagor will pay all costs and
expenses, including reasonable attorneys' fees, which Mortgagee may incur in
connection with any effort or action (whether or not litigation or foreclosure
is involved) to enforce or defend Mortgagee's rights and remedies under any of
the Loan Documents, including but not limited to all attorneys' fees, appraisal
fees, consultants' fees, and other expenses incurred by Mortgagee in securing
title to or possession of, and realizing upon, any security for the Secured
Obligations. All such costs and expenses (together with interest thereon at the
Default Rate from the date that is ten (10) days following demand therefor)
shall constitute part of the Secured Obligations, and may be included in the
computation of the amount owed to Mortgagee for purposes of foreclosing or
otherwise enforcing this Mortgage.

         4.12 FINANCIAL REPORTS. During the term of the Loan, Mortgagor shall
supply to Mortgagee (a) within thirty (30) days following the end of each
quarter, Mortgagor's quarterly and annual operating statements for the Property
as of the end of and for the preceding quarter and fiscal year, as applicable,
in each case prepared against the budget for such year; (b) contemporaneously
with Mortgagor's delivery of each of such operating statements, a certified rent
roll signed and dated by Mortgagor detailing the names of all tenants under the
Leases, the portion of the improvements on the Property occupied by each tenant,
the rent and any other charges payable under each Lease, and the term of each
Lease; and (c) within ninety (90) days following the end of each year, an annual
balance sheet and profit and loss statement of Mortgagor and each Guarantor. The
financial statements and reports described in (a) and (c) above shall be in such
detail as Mortgagee may require, shall be prepared in accordance with generally
accepted accounting principles consistently applied, and shall be certified as
true and correct by Mortgagor or the applicable Guarantor (or, if required by
Mortgagee, by an independent certified public accountant acceptable to Mortgagee
in the case of annual reports). Mortgagor shall also furnish to Mortgagee within
thirty (30) days of Mortgagee's request, any other financial reports or
statements of Mortgagor as Mortgagee may reasonably request. Upon Mortgagee's
demand after any Event of Default, or if Mortgagee securitizes the Loan,
Mortgagor shall supply to Mortgagee the items required in (a) and (b) above on a
monthly basis.

         4.13 PRIORITY OF LEASES. To the extent Mortgagor has the right, under
the terms of any Lease, to make such lease subordinate to the lien hereof,
Mortgagor will, at Mortgagee's request and Mortgagor's expense, take such action
as may be required to effect such subordination. Conversely, Mortgagor will, at
Mortgagee's request and Mortgagor's expense, take such action as may be
necessary to subordinate the lien hereof to any future Lease designated by
Mortgagee.

         4.14 INVENTORIES; ASSEMBLY OF CHATTELS. Mortgagor will, from time to
time at the request of Mortgagee, supply Mortgagee with a current inventory of
the Chattels and the Intangible Personalty, in such detail as Mortgagee may
require. Upon the occurrence of any Event of Default hereunder, Mortgagor will
at Mortgagee's request assemble the Chattels and make them available to
Mortgagee at any place designated by Mortgagee which is reasonably convenient to
both parties.

                                       16
<PAGE>

         4.15 COMPLIANCE WITH LAWS, ETC. Mortgagor shall comply in all material
respects with all applicable laws, rules, regulations and orders, such
compliance to include, without limitation, maintaining all Permits and paying
before the same become delinquent all taxes, assessments and governmental
charges imposed upon Mortgagor or the Property.

         4.16 RECORDS AND BOOKS OF ACCOUNT. Mortgagor shall keep accurate and
complete records and books of account, in which complete entries will be made in
accordance with generally accepted accounting principles consistently applied,
reflecting all financial transactions relating to the Property.

         4.17 INSPECTION RIGHTS. At any reasonable time upon prior written
notice, and from time to time, Mortgagor shall permit Mortgagee, or any agents
or representatives thereof, to examine and make copies of and abstracts from the
records and books of account of, and visit and inspect the Property and to
discuss with Mortgagor the affairs, finances and accounts of Mortgagor.

         4.18 CHANGE OF MORTGAGOR'S ADDRESS OR STATE OF ORGANIZATION. Mortgagor
shall promptly notify Mortgagee if changes are made in Mortgagor's address from
that set forth in SECTION 9.10 hereof, or if Mortgagor shall either change its
"location" (as such term is used in SECTION 5.8 hereof), its state of
organization or if Mortgagor shall organize in any state other than the State
of Delaware.

         4.19 FURTHER ASSURANCES; ESTOPPEL CERTIFICATES. Mortgagor will execute
and deliver to Mortgagee upon demand, and pay the costs of preparation and
recording thereof, any further documents which Mortgagee may request to confirm
or perfect the liens and security interests created or intended to be created
hereby, or to confirm or perfect any evidence of the Secured Obligations.
Mortgagor will also, within ten (10) business days after any request by
Mortgagee, deliver to Mortgagee a signed and acknowledged statement certifying
to Mortgagee, or to any proposed transferee of the Secured Obligations, (a) the
balance of principal, interest, and other sums then outstanding under the Note,
and (b) whether Mortgagor claims to have any offsets or defenses with respect to
the Secured Obligations and, if so, the nature of such offsets or defenses.

         4.20 COSTS OF CLOSING. Mortgagor shall on demand pay directly or
reimburse Mortgagee for any costs or expenses pertaining to the closing of the
Loan, including, but not limited to, fees of counsel for Mortgagee, costs and
expenses for which invoices were not available at the closing of the Loan, or
costs and expenses which are incurred by Mortgagee after such closing. All such
costs and expenses (together with interest thereon at the Default Rate from the
date that is ten (10) days following demand therefor ) shall constitute a part
of the Secured Obligations, and may be included in the computation of the amount
owed to Mortgagee for purposes of foreclosing or otherwise enforcing this
Mortgage.

         4.21 FUND FOR ELECTRONIC TRANSFER. All monthly payments of principal
and interest on the Note, and escrow deposits under this Mortgage, shall be made
by Mortgagor by electronic funds transfer from a bank account established and
maintained by Mortgagor for such purpose. Mortgagor shall establish and maintain
such an account until the Note is fully paid and shall direct the depository of
such account in writing to so transmit such payments on or before

                                       17
<PAGE>

the respective due dates to the account of Mortgagee as shall be designated by
Mortgagee in writing.

         4.22 USE. Mortgagor shall use the Property solely for the operation of
an office/laboratory building, and any other lawful purpose, and for no other
use or purpose.

         4.23 MANAGEMENT. The Property shall be managed by Meredith & Grew,
Incorporated ("Property Manager") under a management agreement previously
delivered to, and approved, by Mortgagee (the "Management Agreement"). Mortgagor
shall not permit any amendment to or modification of the Management Agreement,
or management of the Property by any person or entity other than Property
Manager, without the prior written consent of Mortgagee.

         4.24 CASH MANAGEMENT. From and after the earlier to occur of any Event
of Default, any termination of the Genzyme Lease or any receipt by Mortgagee
from Genzyme of any notice of termination of the Genzyme Lease:

                  (a) Servicer will establish a cash collateral account in the
name of Servicer, as servicer for Mortgagee ("Cash Collateral Account"), at a
bank selected by Mortgagee but reasonably acceptable to Mortgagor (the
"Depository Bank"). Servicer will establish a depository post office box to
accept proceeds and revenues from the Property;

                  (b) Mortgagor shall notify each tenant under the Leases to
remit all amounts due with respect to the Property directly to Servicer for
deposit into the Cash Collateral Account and Mortgagor shall remit to Servicer
all proceeds it receives from operation of the Property;

                  (c) Provided that the event that triggered application of this
SECTION 4.24 was not an Event of Default, and further provided that no Event of
Default has occurred, Mortgagee shall apply amounts deposited into the Cash
Collateral Account first to the operation and maintenance of the Property and
then, at Mortgagee's option, to principal, interest and/or other amounts due
Mortgagee in such order as Mortgagee shall elect. If, however, any Event of
Default shall occur, Mortgagee may apply all funds on deposit from time to time
in the Cash Collateral Account toward payment of the Secured Obligations, in the
order provided in the Note and this Mortgage;

                  (d) Provided that the event that triggered application of this
SECTION 4.24 was not an Event of Default, and further provided that no Event of
Default has occurred, if the Property has achieved a Debt Service Coverage Ratio
(as defined in SECTION 5.4(c)) of at least 1.20 to 1.00 for two consecutive
quarters, based on revenues from the Property generated pursuant to Leases
approved by Mortgagee, Mortgagee will release any excess amounts remaining in
the Cash Collateral Account to Mortgagor and instruct Servicer to thereafter
daily sweep proceeds from the Cash Collateral Account into Mortgagor's operating
account. Thereafter, if the Property shall fail to maintain at least a 1.20 to
1.00 Debt Service Coverage Ratio, each quarter, or if any Event of Default shall
occur, at Mortgagee's option, to be exercised by written notice from Mortgagee
to Mortgagor and Servicer, the provisions of SECTION 4.24(c) shall be reinstated
and the provisions of this SECTION 4.24(d) shall not apply;

                                       18
<PAGE>

                  (e) Upon demand made by Mortgagee, Mortgagor shall execute and
deliver such agreements, documents and items as Mortgagee shall request to
implement the terms of this SECTION 4.24, grant to Mortgagee a security interest
in the Cash Collateral Account and all funds on deposit in the Cash Collateral
Account from time to time, and evidence or perfect such security interest;

                  (f) Mortgagor shall promptly pay, upon demand made by
Mortgagee all costs and expenses incurred by Mortgagee and/or Servicer in
connection with implementing and administering the provisions of this SECTION
4.24, including, without limitation, reasonable attorneys' fees and expenses.
All such costs and expenses (together with interest thereon at the Default Rate
from the date that is ten (10) days following demand therefor) shall constitute
a part of the Secured Obligations, and may be included in the computation of the
amount owed to Mortgagee for purposes of foreclosing or otherwise enforcing this
Mortgage.

                                    ARTICLE 5
                         MORTGAGOR'S NEGATIVE COVENANTS

         5.1 WASTE AND ALTERATIONS. Mortgagor will not commit or permit any
waste with respect to the Property or the Chattels. Mortgagor shall not cause or
permit any part of the Property, including but not limited to any building,
structure, parking lot, driveway, landscape scheme, timber, or other ground
improvement, to be removed, demolished, or materially altered without the prior
written consent of Mortgagee.

         5.2 ZONING AND PRIVATE COVENANTS. Mortgagor will not initiate, join in,
or consent to any change in any zoning ordinance or classification, any change
in the "zone lot" or "zone lots" (or similar zoning unit or units) presently
comprising the Property, any transfer of development rights, any private
restrictive covenant, or any other public or private restriction limiting or
defining the uses which may be made of the Property or any part thereof, without
the express written consent of Mortgagee. If under applicable zoning provisions
the use of all or any part of the Property is or becomes a nonconforming use,
Mortgagor will not cause such use to be discontinued or abandoned without the
express written consent of Mortgagee, and Mortgagor will use its best efforts to
prevent the tenant under any Lease from discontinuing or abandoning such use.

         5.3 INTERFERENCE WITH LEASES.

                  (a) Mortgagor will neither do anything, nor neglect to do any
act required under any Lease, which may cause or permit the termination of any
Lease of all or any part of the Property, or cause or permit the withholding or
abatement of any rent payable under any such Lease.

                  (b) Except as provided in subsection (c) below, without
Mortgagee's prior written consent, which may be granted or withheld in
Mortgagee's sole discretion, Mortgagor shall not enter into or modify any Lease
of all or any part of the Property. Any submission by Mortgagor for Mortgagee's
approval of a Lease or modification thereof shall be accompanied by a copy of
such Lease or modification, a Lease abstract, a then-current rent roll for the
Property, year-to-date and prior year operating statements for the Property, and
a cover

                                       19
<PAGE>

letter requesting Mortgagee's approval which contains a signature line on which
Mortgagee may evidence its approval of such Lease or modification.

                  (c) Notwithstanding the provisions of subsection (b), above,
Mortgagor shall be permitted to enter into ground floor retail Leases, without
Mortgagee's prior written consent, provided such Leases are on market terms.
Mortgagor shall provide to Mortgagee a copy of any retail Lease entered into
without Mortgagee's consent within ten (10) days following its execution.

                  (d) Except with the prior written consent of Mortgagee, which
may be granted or withheld in Mortgagee's sole discretion, Mortgagor will not
(i) collect rent from all or any part of the Property for more than one month in
advance, (ii) assign the rents from the Property or any part thereof, or (iii)
consent to the cancellation or surrender of all or any part of any Lease, except
that Mortgagor may in good faith terminate any Lease for nonpayment of rent or
other material breach by the tenant.

         5.4 TRANSFER OR FURTHER ENCUMBRANCE OF PROPERTY.

                  (a) Without Mortgagee's prior written consent, which consent
may be granted or withheld in Mortgagee's sole and absolute discretion,
Mortgagor shall not (i) sell, assign, convey, transfer or otherwise dispose of
any legal, beneficial or equitable interest in all or any part of the Property,
(ii) permit or suffer any owner, directly or indirectly, of any beneficial
interest in the Property or Mortgagor to transfer such interest, whether by
transfer of partnership, membership, stock or other beneficial interest in any
entity or otherwise, or (iii) mortgage, hypothecate or otherwise encumber or
permit to be encumbered or grant or permit to be granted a security interest in
all or any part of the Property or Mortgagor or any beneficial or equitable
interest in either the Property or Mortgagor. The provisions of this Section
shall not prohibit transfers of title or interest under any will or testament or
applicable law of descent.

                  (b) Notwithstanding the provisions of SECTION 5.4(a) to the
contrary, Mortgagee shall permit a one-time transfer of the Property provided
that all of the following conditions are satisfied: (i) no Event of Default has
occurred and no Default has occurred and is continuing; (ii) Mortgagor has paid
to Mortgagee an assumption fee of one percent (1%) of the outstanding principal
balance of the Secured Obligations; (iii) if the proposed transferee is a land
trust, Mortgagee has received a first-lien collateral assignment of all
beneficial interest therein; (iv) Mortgagee has received and has had a
reasonable opportunity to review all documents and agreements executed or to be
executed in connection with the proposed transfer; (v) the non-economic terms
(e.g., those terms other than interest rate, payment schedule, principal
balance, and non-recourse nature (subject to exceptions thereto customarily
included by Mortgagee in loan documents)) of the Loan Documents have been
modified as Mortgagee may request in good faith; (vi) the proposed transferee
has assumed all of Mortgagor's obligations under the Loan Documents; (vii)
Mortgagee has received at least thirty (30) days' prior written notice of the
proposed transfer; (viii) the proposed transferee and its equity owners have, in
the sole judgment of Mortgagee exercised in good faith, a net worth equal to the
net worth of Mortgagor as of the date hereof or otherwise satisfactory to
Mortgagee, and a satisfactory history of owning, operating and leasing property
similar to the Property; (ix) the proposed transferee and its equity owners
have, in the sole judgment of Mortgagee exercised in good faith, a satisfactory
credit

                                       20
<PAGE>

history and professional reputation and character; (x)the Debt Service Coverage
Ratio (as hereinafter defined) is not less than 2.25x, and Mortgagee receives
satisfactory evidence that such ratio will be maintained for the succeeding
twelve (12) months; (xi)the Loan-to-Value Ratio (as hereinafter defined), taking
into account all obligations secured by liens on the Property does not exceed
60%; (xii) Mortgagor pays all costs and expenses incurred by Mortgagee in
connection with such transfer, including, without limitation, all legal,
processing, accounting, title insurance, and appraisal fees, whether or not such
transfer is actually consummated; (xiii) at Mortgagee's option, Mortgagee has
received an endorsement to its mortgagee's title insurance policy at Mortgagor's
expense, which endorsement states that the lien of the Mortgage remains a first
and prior lien against the Property subject to no exceptions other than as
approved by Mortgagee; (xiv) principals of the proposed transferee acceptable to
Mortgagee in its sole discretion execute a guaranty agreement in the form of the
Guaranty Agreement and an environmental indemnity agreement in the form of the
Environmental Indemnity Agreement; and (xv) the Mezzanine Lean (hereinafter
defined) is paid off, and all liens and/or security interests thereunder
released of record. Upon the satisfaction of the foregoing conditions, Mortgagee
shall release Mortgagor and Guarantor from liability under the Loan Documents
except to the extent that, prior to such release, any full-recourse liability
has arisen under any of the Loan Documents. The foregoing right to transfer the
Property shall terminate upon conveyance of the Property by the initial
Mortgagor named herein.

                  (c) The term "Debt Service Coverage Ratio" shall mean the
ratio, as reasonably determined by Mortgagee, of (i) Net Operating Income for
the Property for the preceding twelve (12) calendar months, to (ii) the annual
debt service payments due under the Loan (provided, however, that the annual
debt service payments shall exclude any Required Additional Payments (as defined
in the Note)) and on all other indebtedness secured, or to be secured, by a lien
on all or any part of the Property, where "Net Operating Income" shall mean all
gross revenues generated by the Property (excluding loans or contributions to
capital), less operating expenses (other than debt service payments due under
the Loan), as determined on a cash accounting basis, as of the date of such
calculation for the period in question, adjusted, however, so that (A) operating
expenses shall be deemed to include (1) a management fee equal to the greater of
the actual management fee for the Property or four percent (4%) of gross
revenues, and (2) a tenant improvement, leasing commission, and capital
improvement reserve equal to $0.75 per rentable square foot per year (B)
payments of operating expenses, including property taxes and assessments and
insurance expenses, are to be spread out over the period during which they
accrued and shall be adjusted for any known future changes to any such expenses,
(C) prepaid rents and other prepaid payments received are to be spread out over
the periods during which such rents or payments are earned or applicable, (D)
security deposits shall not be included as items of income until duly applied or
earned, (E) gross revenue shall be based on a lease-in-place analysis which
reflects then current Leases in place, as determined by Mortgagee, in its
reasonable discretion, in accordance with its standard underwriting criteria,
consistently applied, and excluding extraordinary, or one time items, and (F)
any refunds or rebates to operating expenses are to be applied and credited
against the applicable operating expenses for the period that such operating
expenses were incurred. Debt Service Coverage Ratio shall be calculated on a
cash flow basis. The "Loan-to-Value Ratio" shall be the ratio, as determined by
Mortgagee, of the aggregate principal balance of the Note and all other
indebtedness secured by liens or encumbrances against the Property to the fair
market value of the Property, as such fair market value is determined by an
M.A.I. appraisal satisfactory to

                                       21
<PAGE>

Mortgagee (the "Appraisal"). Upon Mortgagee's request, Mortgagor shall deliver
the appraisal to Mortgagee at Mortgagor's sole cost and expense.

                  (d) Further, notwithstanding the provisions of SECTION 5.4(a)
hereinabove, no transfer fees shall be due with respect to, and Mortgagee's
prior written consent shall not be required for, any transfers that meet the
following criteria:

                           (i) a reorganization of the ownership and control of
         Guarantor, in connection with a separation of Guarantor's commercial
         real estate asset holdings from its timber asset holdings (a "Lyme
         Timber Reorganization"), provided that after such Lyme Timber
         Reorganization: (A) the resulting entity has a net worth (1) equal to
         or greater than 80% of the net worth on the date hereof of Guarantor
         (it being understood that the value of the Property shall be excluded
         from the calculation of both Guarantor and the resulting entity), or
         (2) is otherwise acceptable to Mortgagee in its sole discretion; (B)
         the day to day operations and decisions of the resulting entity are
         managed, directly or indirectly, by David E. Clem, Robert L. Green or
         such other individual having significant experience in the management
         of properties similar to the Property as may be approved by Mortgagee
         in its sole but good faith discretion (a "Substitute Principal"); and
         (C) the resulting entity either: (1) executes and delivers to Mortgagee
         a Guaranty Agreement and Environmental Indemnity Agreement
         substantially identical to those executed and delivered by Guarantor to
         Mortgagee in connection with the closing of the Loan; or (2) if the net
         worth of such resulting entity is not equal to or greater than 80% of
         such net worth of Guarantor or otherwise acceptable to Mortgagee in its
         sole discretion, as provided above, causes all of David E. Clem, Robert
         L. Green and the Substitute Principal that manage and control the
         resulting entity following a Lyme Timber Reorganization to execute and
         deliver to Mortgagee a Guaranty Agreement and Environmental Indemnity
         Agreement substantially identical to those executed and delivered by
         Guarantor to Mortgagee in "connection with the closing of the Loan (it
         being understood that in the event of a reorganization pursuant to this
         subsection (i) and satisfaction of the other conditions set forth
         herein, Guarantor shall be released from its obligations as Guarantor
         and pursuant to the Environmental Indemnity Agreement);

                           (ii) any direct or indirect transfer of interests in
         (A) Kendall Square, LLC ("KS"), the sole owner of Mortgagor, (B)
         Guarantor or any successor entity into which it merges or otherwise
         consolidates or which acquires a majority of its commercial property
         assets similar to the Property as a result of a Lyme Timber
         Reorganization (the "Lyme Owner"), or (C) any entities owned in whole
         or part by the Lyme Owner or the Scottish Widows Owner (described
         below), and directly or indirectly owning KS in whole or part, as long
         as (1) David E. Clem, Robert L. Green or a Substitute Principal,
         directly or indirectly, manage the day to day operations and decisions
         of the Lyme Owner (with respect to its commercial real estate
         operations), KS and Mortgagor, and (2) no change in ownership control
         of the Lyme Owner, the Scottish Widows Owner, KS or Mortgagor occurs;

                           (iii) any transfer of interests in KS (A) to the Lyme
         Owner, Lyme CRP, LLC or any entity wholly owned by either the Lyme
         Owner or Lyme CRP, LLC, or (B) by Lyme CRP, LLC to Morrison Street, LLC
         or any entity that directly or

                                       22
<PAGE>

         indirectly owns all of the membership interests in Morrison Street, LLC
         (collectively, the "Scottish Widows Owner"), provided that upon and
         after any such transfer after which the Lyme Owner will not manage or
         control management of the Mortgagor and the Property: (1) a substitute
         "Guarantor" acceptable to Mortgagee, in Mortgagee's sole discretion,
         shall execute and deliver to Mortgagee a Guaranty Agreement and
         Environmental Indemnity Agreement substantially identical to those
         executed and delivered by Guarantor to Mortgagee in connection with the
         closing of the Loan, (2) the Property shall be managed by a property
         manager approved by Mortgagee in its sole discretion pursuant to a
         management agreement approved by Mortgagee in its sole discretion, and
         (3) if a transfer of ownership control of any Scottish Widows Owner has
         previously occurred pursuant to SECTION 5.4(d)(iv)(A), then such
         entity, and such entity having ownership control over such Scottish
         Widows Owner, shall be acceptable to Mortgagee (it being understood
         that in the event of a transfer pursuant to this subsection (iii) after
         which the Lyme Owner will not manage or control management of the
         Mortgagor and the Property and the satisfaction of the other conditions
         set forth herein, Guarantor (or the then applicable successor guarantor
         immediately prior to such reorganization) shall be released from its
         obligations as Guarantor and pursuant to the Environmental Indemnity
         Agreement);

                           (iv) (A) a transfer of ownership control of any
         Scottish Widows Owner to an entity acceptable to Mortgagee (provided
         that Mortgagee's consent to such entity shall only be required if a
         transfer described in SECTION 5.4(d)(iii)(B), above, has previously
         occurred), provided that after such transfer the applicable Scottish
         Widows Owner (or the entity that directly or indirectly owns all of the
         owners' interests in such Scottish Widows Owner) shall have a net worth
         of at least one billion dollars ($1,000,000,000.00), as reasonably
         determined by Mortgagee, or (B) transfers of any publicly-traded shares
         of stock in any Scottish Widows Owner that does not result in a
         transfer of ownership control of such Scottish Widows Owner; or

                           (v) provided that Mortgagor has paid to Mortgagee a
         fee equal to one fourth of one percent (.25%) of the then outstanding
         balance of the Loan, any Mezzanine Loan with respect to the Mortgagor.
         "Mezzanine Loan" shall mean a loan satisfying the following criteria:
         (A) the amount of the Mezzanine Loan shall not exceed the lesser of
         $25,000,000.00, or an amount which would cause the loan-to-value ratio
         (taking into account the outstanding principal balance of the Loan and
         the Mezzanine Loan) to equal 80%, as determined by Mortgagee; (B) the
         Debt Service Coverage Ratio (as defined above, but taking into account
         both the debt service due under the Loan and Mezzanine Loan) shall not
         be less than 1.25x; (C) no "balloon" payment shall be due under such
         Mezzanine Loan prior to the Original Maturity Date (as defined in the
         Note); (D) payment of the Mezzanine Loan may only be secured by pledges
         of membership interests in Mortgagor or KS, and shall not be secured by
         any interest in the Property; (E) the lender of such Mezzanine Loan
         (the "Mezzanine Lender") shall, in the sole judgment of Mortgagee
         exercised in good faith, have (1) a satisfactory history of owning,
         operating and leasing property similar to the Property, and (2) a
         satisfactory credit history and professional reputation and character;
         and (F) Mortgagee and Mezzanine Lender shall enter into an
         Intercreditor and Subordination Agreement acceptable to Mortgagee in
         its sole discretion, consistent with all of the foregoing, and
         providing, without limitation:

                                       23
<PAGE>

         (1) upon the occurrence of an Event of a Default under the Loan,
         Mortgagee may take any and all action available to it under the Loan
         Documents and exercise all remedies available under the Loan Documents,
         and Mezzanine Lender will not exercise any rights or remedies available
         to it and no payments shall be paid by Mortgagor to Mezzanine Lender
         until and unless the Secured Obligations have been fully paid; (2)
         prior to Mortgagee commencing any enforcement action under the Loan
         Documents, Mortgagee shall, provide written notice of the default which
         would permit the Mortgagee to commence such enforcement action to
         Mezzanine Lender, whether or not Mortgagee is obligated to give notice
         thereof to Mortgagor (each, a "Senior Loan Default Notice") and shall
         permit Mezzanine Lender an opportunity to cure such default in
         accordance with the following provisions: (I) if the default is a
         monetary default, Mezzanine Lender shall have until five (5) business
         days after the later of (x) the giving by Mortgagee of the Senior Loan
         Default Notice, and (y) the expiration of Mortgagor's cure provision if
         any, to cure such monetary default, but Mezzanine Lender shall not have
         the right to cure as hereinabove set forth with respect to monthly
         scheduled debt service payments on the Loan for a period of more than
         two (2) consecutive months unless Mezzanine Lender has commenced and is
         continuing to diligently pursue its rights against its collateral for
         the Mezzanine Loan, and (II) if the default is of a non-monetary
         nature, Mezzanine Lender shall have the same period of time as the
         Mortgagor under the Loan Documents to cure such non-monetary default;
         (3) no modifications shall be made to the Mezzanine Loan without
         Mortgagee's consent; and (4) in the event of a bankruptcy or similar
         filing by or against Mortgagor or any direct or indirect owner of
         Mortgagor, Mezzanine Lender shall assign to Mortgagee all of Mezzanine
         Lender's plan voting rights and shall not:

                  (a)      Take any action available under Mezzanine Lender's
                           security documents until the Secured Obligations are
                           paid in full;

                  (b)      Commence or join with any other creditor of Mortgagor
                           in a bankruptcy proceeding;

                  (c)      Vote for any plan of reorganization that is not
                           supported by Mortgagee;

                  (d)      Object to any cash collateral order proposed or
                           endorsed by Mortgagee;

                  (e)      Object to any motion by Mortgagee to lift the
                           automatic stay; or

                  (f)      Transfer or assign the Mezzanine Loan or any interest
                           therein.

         Any references in this section to persons having "management control"
         or "managing and controlling" any entity shall mean persons having the
         power and authority to direct, or cause the direction of, the
         management and policies of such entity and to conduct the day-to-day
         operations of such entity.

         5.5 FURTHER ENCUMBRANCE OF CHATTELS. Mortgagor will neither create nor
permit any lien, security interest or encumbrance against the Chattels or
Intangible Personalty or

                                       24
<PAGE>

any part thereof or interest therein, other than the liens and security
interests created by the Loan Documents, without the prior written consent of
Mortgagee, which may be withheld for any reason. Notwithstanding the preceding
sentence, however, Mortgagor will not be deemed to be in default under this
Section if and so long as Mortgagor (a) contests in good faith the validity or
amount of any asserted involuntary lien and diligently prosecutes or defends an
action appropriate to obtain a binding determination of the disputed matter, (b)
provides Mortgagee with such security as Mortgagee may require to protect
Mortgagee against all loss, damage, and expense, including reasonable attorneys'
fees, which Mortgagee might incur if the asserted involuntary lien is determined
to be valid.

         5.6 ASSESSMENTS AGAINST PROPERTY. Mortgagor will not, without the prior
written approval of Mortgagee, which may be withheld for any reason, consent to
or allow the creation of any so-called special districts, special improvement
districts, benefit assessment districts or similar districts, or any other body
or entity of any type, or allow to occur any other event, that would or might
result in the imposition of any additional taxes, assessments or other monetary
obligations or burdens on the Property, and this provision shall serve as RECORD
NOTICE to any such district or districts or any governmental entity under whose
authority such district or districts exist or are being formed that, should
Mortgagor or any other person or entity include all or any portion of the
Property in such district or districts, whether formed or in the process of
formation, without first obtaining Mortgagee's express written consent, the
rights of Mortgagee in the Property pursuant to this Mortgage or following any
foreclosure of this Mortgage, and the rights of any person or entity to whom
Mortgagee might transfer the Property following a foreclosure of this Mortgage,
shall be senior and superior to any taxes, charges, fees, assessments or other
impositions of any kind or nature whatsoever, or liens (whether statutory,
contractual or otherwise) levied or imposed, or to be levied or imposed, upon
the Property or any portion thereof as a result of inclusion of the Property in
such district or districts.

         5.7 TRANSFER OR REMOVAL OF CHATTELS. Mortgagor will not sell, transfer
or remove from the Property all or any part of the Chattels, unless the items
sold, transferred, or removed are simultaneously replaced with similar items of
equal or greater value.

         5.8 CHANGE OF NAME, ORGANIZATIONAL I.D. NO. OR LOCATION. Mortgagor will
not change the name under which Mortgagor does business (or adopt or begin doing
business under any other name or assumed or trade name), change its
organizational identification number, or change its location, without first
notifying Mortgagee of Mortgagor's intention to do so and delivering to
Mortgagee such organizational documents of Mortgagor and executed modifications
or supplements to this Mortgage (and to any financing statement which may be
filed in connection herewith) as Mortgagee may require. For purposes of the
foregoing, Mortgagor's "location" shall mean (a) if Mortgagor is a registered
organization, Mortgagor's state of registration, (b) if Mortgagor is an
individual, the state of Mortgagor's principal residence, or (c) if Mortgagor is
neither a registered organization nor an individual, the state in which
Mortgagor's place of business (or, if Mortgagor has more than one place of
business, the Mortgagor's chief executive office) is located.

         5.9 IMPROPER USE OF PROPERTY OR CHATTELS. Mortgagor will not use the
Property or the Chattels for any purpose or in any manner which violates any
applicable law,

                                       25
<PAGE>

ordinance, or other governmental requirement, the requirements or conditions of
any insurance policy, or soy private covenant.

         5.10 ERISA. Mortgagor shall not engage in any transaction which would
cause the Note (or the exercise by Mortgagee of any of its rights under the Loan
Documents) to be a non-exempt, prohibited transaction under ERISA (including
for this purpose the parallel provisions of Section 4975 of the Internal Revenue
Code of 1986, as amended), or otherwise result in Mortgagee being deemed in
violation of any applicable provisions of ERISA. Mortgagor shall indemnify,
protect, defend, and hold Mortgagee harmless from and against any and all
losses, liabilities, damages, claims, judgments, costs, and expenses (including,
without limitation attorneys' fees and costs incurred in the investigation,
defense, and settlement of claims and in obtaining any individual ERISA
exemption or state administrative exception that may be required, in Mortgagee's
sole and absolute discretion) that Mortgagee may incur, directly or indirectly,
as the result of the breach by Mortgagor of any warranty or representation set
forth in SECTION 3.3(X) hereof or the breach by Mortgagor of any covenant
contained in this Section. This indemnity shall survive any termination,
satisfaction or foreclosure of this Mortgage and shall not be subject to the
limitation on personal liability described in the Note.

         5.11 USE OF PROCEEDS. Mortgagor will not use any funds advanced by
Mortgagee under the Loan Documents for household or agricultural purposes, to
purchase margin stock, or for any purpose prohibited by law.

         5.12 ACQUISITION OF OTHER REAL PROPERTY. Mortgagor will not acquire or
own any real property other than the Property (which includes the "Leasehold
Estate" described in the Addendum attached hereto).

                                    ARTICLE 6
                               EVENTS OF DEFAULT

         Each of the following events will constitute an event of default (an
"Event of Default") under this Mortgage and under each of the other Loan
Documents:

         6.1 FAILURE TO PAY NOTE. Mortgagor's failure to make any payment when
due under the terms of the Note or any other Loan Document; provided, however,
that Mortgagor shall be permitted to make one (1) payment due under the Note
within five (5) days following its due date in any consecutive twelve (12) month
period without such event constituting an Event of Default.

         6.2 DUE ON SALE OR ENCUMBRANCE. The occurrence of any violation of any
covenant contained in Section 5.4, 5.5 or 5.7 hereof and the failure of such
violation to be remedied within thirty (30) days following written notice from
Mortgagee to Mortgagor.

         6.3 OTHER OBLIGATIONS. The failure of Mortgagor to properly perform any
obligation contained herein or in any of the other Loan Documents (other than
the obligation to make payments under the Note or the other Loan Documents) and
the continuance of such failure for a period of thirty (30) days following
written notice thereof from Mortgagee to Mortgagor; provided, however, that if
such failure is not curable within such thirty (30) day period, then, so long as
Mortgagor commences to cure such failure within such thirty (30) day

                                       26
<PAGE>

period and is continually and diligently attempting to cure to completion, such
failure shall not be an Event of Default unless such failure remains uncured for
one hundred twenty (120) days after such written notice to Mortgagor; provided,
further, that if Mortgagee shall so elect in the exercise of its sole but good
faith discretion, then after such one hundred twenty (120) day period, and for
so long as Mortgagor is continually and diligently attempting to cure to
completion, such failure shall not be an Event of Default so long as Mortgagor
provides to Mortgagee such additional security to adequately protect Mortgagee
as is acceptable to Mortgagee in the exercise of its sole but good faith
discretion.

         6.4 LEVY AGAINST PROPERTY. The levy against any of the Property,
Chattels or Intangible Personalty, of any execution, attachment, sequestration
or other writ and the failure of the levy to be removed or discharged (or bonded
over to the satisfaction of Mortgagee) within thirty (30) days following written
notice from Mortgagee to Mortgagor.

         6.5 LIQUIDATION. The liquidation, termination or dissolution of
Mortgagor or Guarantor.

         6.6 APPOINTMENT OF RECEIVER. The appointment of a trustee or receiver
for the assets, or any part thereof, of Mortgagor or Guarantor, or the
appointment of a trustee or receiver for any real or personal property, or the
like, or any part thereof, representing the security for the Secured Obligations
and the failure of such trustee or receiver to be discharged within sixty (60)
days after such appointment.

         6.7 ASSIGNMENTS. The making by Mortgagor or Guarantor of a transfer in
fraud of creditors or an assignment for the benefit of creditors.

         6.8 ORDER FOR RELIEF. The entry in bankruptcy of an order for relief
for or against Mortgagor or Guarantor.

         6.9 BANKRUPTCY. The filing of any petition (or answer admitting the
material allegations of any petition), or other pleading, seeking entry of an
order for relief for or against Mortgagor or Guarantor as a debtor or bankrupt
or seeking an adjustment of any of such parties' debts, or any other relief
under any state or federal bankruptcy, reorganization, debtor's relief or
Insolvency laws now or hereafter existing, including, without limitation, a
petition or answer seeking reorganization or admitting the material allegations
of a petition filed against any such party in any bankruptcy or reorganization
proceeding, or the act of any of such parties in instituting or voluntarily
being or becoming a party to any other judicial proceedings intended to effect a
discharge of the debts of any such parties, in whole or in part, or a
postponement of the maturity or the collection thereof, or a suspension of any
of the rights or powers of a trustee or of any of the rights or powers granted
to Mortgagee herein, or in any other document executed in connection herewith;
provided, however, that no Event of Default shall occur under this Section if an
involuntary bankruptcy or insolvency petition is filed against Mortgagor or
Guarantor unless such petition is not dismissed within sixty (60) days following
its filing.

         6.10 MISREPRESENTATION. If any representation or warranty made by
Mortgagor or Guarantor, or in any of the other Loan Documents or any other
instrument or document

                                       27
<PAGE>

modifying, renewing, extending, evidencing, securing or pertaining to the Note
is false, misleading or erroneous in any material respect when made.

         6.11 JUDGMENTS. The failure of Mortgagor or Guarantor to pay any money
judgment in excess of $10,000.00 against any such party before the expiration of
thirty (30) days after such judgment becomes final and no longer appealable.

         6.12 ADMISSIONS REGARDING DEBTS. The admission of Mortgagor or
Guarantor in writing of any such party's inability to pay such party's debts as
they become due.

         6.13 ASSERTION OF PRIORITY. The assertion of any claim of priority over
this Mortgage, by title, lien, or otherwise, unless Mortgagor within thirty (30)
days after such assertion either causes the assertion to be withdrawn or
provides Mortgagee with such security as Mortgagee may require to protect
Mortgagee against all loss, damage, or expense, including attorneys' fees, which
Mortgagee may incur in the event such assertion is upheld.

         6.14 OTHER LOAN DOCUMENTS. The occurrence of any default by Mortgagor,
after the lapse of any applicable grace or cure period, or the occurrence of any
event or circumstance defined as an Event of Default, under any of the Loan
Documents other than this Mortgage.

         6.15 OTHER LIENS. The occurrence of any default by Mortgagor, after the
lapse of any applicable grace or cure period, or the occurrence of any event or
circumstance defined as an Event of Default, under any other consensual lien
encumbering the Property, or any part thereof or interest therein, or any
document or instrument evidencing obligations secured thereby.

         6.16 OTHER INDEBTEDNESS. The occurrence of any default by Mortgagor,
after the lapse of any applicable grace or cure period, or the occurrence of any
event or circumstance defined as an Event of Default, under any other
indebtedness incurred or owing by Mortgagor, or any document or instrument
evidencing any obligation to pay such indebtedness.

                                    ARTICLE 7
                              MORTGAGEE'S REMEDIES

         Immediately upon or any time after the occurrence of any Event of
Default hereunder, Mortgagee may exercise any remedy available at law or in
equity, including but not limited to those listed below and those listed in the
other Loan Documents, in such sequence or combination as Mortgagee may determine
in Mortgagee's sole discretion:

         7.1 PERFORMANCE OF DEFAULTED OBLIGATIONS. Mortgagee may make any
payment or perform any other obligation under the Loan Documents which Mortgagor
has failed to make or perform, and Mortgagor hereby irrevocably appoints
Mortgagee as the true and lawful attorney-in-fact for Mortgagor to make any such
payment and perform any such obligation in the name of Mortgagor. All payments
made and expenses (including attorneys' fees) incurred by Mortgagee in this
connection, together with interest thereon at the Default Rate from the date
paid or incurred until repaid, will be part of the Secured Obligations and will
be immediately due and payable by Mortgagor to Mortgagee. In lieu of advancing
Mortgagee's

                                       28
<PAGE>

own funds for such purposes, Mortgagee may use any funds of Mortgagor which may
be in Mortgagee's possession, including but not limited to insurance or
condemnation proceeds and amounts deposited for taxes, insurance premiums, or
other purposes.

         7.2 SPECIFIC PERFORMANCE AND INJUNCTIVE RELIEF. Notwithstanding the
availability of legal remedies, but subject to the non-recourse provisions of
the Note, Mortgagee will be entitled to obtain specific performance, mandatory
or prohibitory injunctive relief, or other equitable relief requiring Mortgagor
to cure or refrain from repeating any Default.

         7.3 ACCELERATION OF SECURED OBLIGATIONS. Mortgagee may, without notice
or demand, declare all of the Secured Obligations immediately due and payable in
full.

         7.4 SUIT FOR MONETARY RELIEF. Subject to the non-recourse provisions of
the Note, with or without accelerating the maturity of the Secured Obligations,
Mortgagee may sue from time to time for any payment due under any of the Loan
Documents, or for money damages resulting from Mortgagor's default under any of
the Loan Documents.

         7.5 POSSESSION OF PROPERTY. To the extent permitted by law, Mortgagee
may enter and take possession of the Property without seeking or obtaining the
appointment of a receiver, may employ a managing agent for the Property, and may
lease or rent all or any part of the Property, either in Mortgagee's name or in
the name of Mortgagor, and may collect the rents, issues, and profits of the
Property. Any revenues collected by Mortgagee under this Section will be applied
first toward payment of all expenses (including attorneys' fees) incurred by
Mortgagee, together with interest thereon at the Default Rate from the date
incurred until repaid, and the balance, if any, will be applied against the
Secured Obligations in such order and manner as Mortgagee may elect in its sole
discretion.

         7.6 ENFORCEMENT OF SECURITY INTERESTS. Mortgagee may exercise all
rights of a secured party under the Code with respect to the Chattels and the
Intangible Personalty, including but not limited to taking possession of,
holding, and selling the Chattels and enforcing or otherwise realizing upon any
accounts and general intangibles. Any requirement for reasonable notice of the
time and place of any public sale, or of the time after which any private sale
or other disposition is to be made, will be satisfied by Mortgagee's giving of
such notice to Mortgagor at least ten (10) days prior to the time of any public
sale or the time after which any private sale or other intended disposition is
to be made.

         7.7 FORECLOSURE AGAINST PROPERTY.

                  (a) Mortgagee may bring an action in any court of competent
jurisdiction to foreclose this Mortgage or foreclose this Mortgage in any other
manner permitted by applicable law. Mortgagor agrees that, in case Mortgagee in
the exercise of the Power of Sale herein given elects to sell in parcels, such
sales may be held from time to time and the Power of Sale shall not be exhausted
until all of the Property shall have been sold; and that Mortgagee shall have
the additional right and power to sell the whole of the Property notwithstanding
that the proceeds of such sales exceed or may exceed the sum of money then
secured hereby. In the event of any separate sale of the Collateral, Mortgagor
shall be entitled to reasonable notice of the time and place of any public sale
or of the time after which any private sale or other intended

                                       29
<PAGE>

disposition thereof is to be made, and such requirement of reasonable notice
shall be met if such notice is mailed postage prepaid, to the address of
Mortgagor as set forth in this Mortgage at least five (5) days before the time
of such sale or other disposition. At any foreclosure sale, the Property or any
combination or all of any other security for the Secured Obligations or any part
thereof may be offered for sale for one total price, and the proceeds of such
sale may be accounted for in one account without distinction between the items
of security and without assigning to them any proportion of such proceeds,
Mortgagor hereby waiving the application of any doctrine of marshalling of
assets.

                  (b) All third-party fees, costs and expenses of any kind
incurred by Mortgagee in connection with foreclosure of this Mortgage,
including, without limitation, the costs of any appraisals of the Property
obtained by Mortgagee, the cost of any title reports or abstracts, all costs of
any receivership for the Property advanced by Mortgagee, and all attorneys' and
consultants' fees and expenses incurred by Mortgagee, shall constitute a part of
the Secured Obligations and may be included as part of the amount owing from
Mortgagor to Mortgagee at any foreclosure sale.

                  (c) The proceeds of any sale under this Section shall be
applied first to the fees and expenses of the officer conducting the sale, and
then to the reduction or discharge of the Secured Obligations in such order and
manner as Mortgagee may elect in its sole discretion; any surplus remaining
shall be paid over to Mortgagor or to such other person or persons as may be
lawfully entitled to such surplus.

                  (d) Nothing in this Section dealing with foreclosure
procedures or specifying particular actions to be taken by Mortgagee shall be
deemed to contradict or add to the requirements and procedures now or hereafter
specified by Massachusetts law, and any such inconsistency shall be resolved in
favor of Massachusetts law applicable at the time of foreclosure.

         7.8 APPOINTMENT OF RECEIVER. To the extent permitted by law, Mortgagee
shall be entitled, as a matter of absolute right and without regard to the value
of any security for the Secured Obligations or the solvency of any person liable
therefor, to the appointment of a receiver for the Property upon ex-parte
application to any court of competent jurisdiction. Mortgagor waives any right
to any hearing or notice of hearing prior to the appointment of a receiver. Such
receiver and its agents shall be empowered to (a) take possession of the
Property and any businesses conducted by Mortgagor or any other person thereon
and any business assets used in connection therewith, (b) exclude Mortgagor and
Mortgagor's agents, servants, and employees from the Property, (c) collect the
rents, issues, profits, and income therefrom, (d) complete any construction
which may be in progress, (e) do such maintenance and make such repairs and
alterations as the receiver deems necessary, (f) use all stores of materials,
supplies, and maintenance equipment on the Property and replace such items at
the expense of the receivership estate, (g) pay all taxes and assessments
against the Property and the Chattels, all premiums for insurance thereon, all
utility and other operating expenses, and all sums due under any prior or
subsequent encumbrance, (h) lease the Property or any part thereof, and (i)
generally do anything which Mortgagor could legally do if Mortgagor were in
possession of the Property. All expenses incurred by the receiver or its agents
shall constitute a part of the Secured Obligations. Any revenues collected by
the receiver shall be applied first to the expenses of the

                                       30
<PAGE>

receivership, including attorneys' fees incurred by the receiver and by
Mortgagee, together with interest thereon at the Default Rate from the date
incurred until repaid, and the balance shall be applied toward the Secured
Obligations in such order or manner as Mortgagee may in its sole discretion
elect or in such other manner as the court may direct. Unless sooner terminated
with the express consent of Mortgagee, any such receivership will continue until
the Secured Obligations have been discharged in full, or until title to the
Property has passed after foreclosure sale and all applicable periods of
redemption have expired.

         7.9 RIGHT TO MAKE REPAIRS, IMPROVEMENTS. Should any part of the
Property come into the possession of Mortgagee, Mortgagee may use, operate,
and/or make repairs, alterations, additions and improvements to the Property for
the purpose of preserving it or its value. Subject to the non-recourse
provisions of the Note, Mortgagor covenants to promptly reimburse and pay to
Mortgagee, at the place where the Note is payable, or at such other place as may
be designated by Mortgagee in writing, the amount of all reasonable expenses
(including the cost of any insurance, taxes, or other charges) incurred by
Mortgagee in connection with its custody, preservation, use or operation of the
Property, together with interest thereon from the date incurred by Mortgagee at
the Default Rate, and all such expenses, costs, taxes, interest, and other
charges shall be a part of the Secured Obligations. It is agreed, however, that
the risk of accidental loss or damage to the Property is undertaken by Mortgagor
and Mortgagee shall have no liability whatsoever for decline in value of the
Property, for failure to obtain or maintain insurance, or for failure to
determine whether any insurance ever in force is adequate as to amount or as to
the risks insured.

         7.10 SURRENDER OF INSURANCE. Mortgagee may surrender the insurance
policies maintained pursuant to the terms hereof, or any part thereof, and
receive and apply the unearned premiums as a credit on the Secured Obligations
and, in connection therewith, Mortgagor hereby appoints Mortgagee (or any
officer of Mortgagee), as the true and lawful agent and attorney-in-fact for
Mortgagor (with full powers of substitution), which power of attorney shall be
deemed to be a power coupled with an interest and therefore irrevocable, to
collect such premiums.

         7.11 PRIMA FACIE EVIDENCE. Mortgagor agrees that, in any assignments,
deeds, bills of sale, notices of sale, or postings, given by Mortgagee, any and
all statements of fact or other recitals therein made as to the identity of
Mortgagee, or as to the occurrence or existence of any Event of Default, or as
to the acceleration of the maturity of the Secured Obligations, or as to the
request to sell, posting of notice of sale, notice of sale, time, place, terms
and manner of sale and receipt, distribution and application of the money
realized therefrom, and without being limited by the foregoing, as to any other
act or thing having been duly done by Mortgagee, shall be taken by all courts of
law and equity as prima facie evidence that such statements or recitals state
facts and are without further question to be so accepted, and Mortgagor does
hereby ratify and confirm any and all acts that Mortgagee may lawfully do by
virtue hereof.

                                       31
<PAGE>

                                    ARTICLE 8
                         ASSIGNMENT OF LEASES AND RENTS

         8.1 ASSIGNMENT OF LEASES AND RENTS. Mortgagor hereby unconditionally
and absolutely grants, transfers and assigns unto Mortgagee all rents,
royalties, issues, profits and income ("Rents") now or hereafter due or payable
for the occupancy or use of the Property, and all Leases, whether written or
oral, with all security therefor, including all guaranties thereof now or
hereafter affecting the Property; reserving unto Mortgagor, however, a license
to collect and retain such Rents prior to the occurrence of any Event of
Default. Such license shall be revocable by Mortgagee without notice to
Mortgagor at any time after the occurrence of an Event of Default. Mortgagor
represents that the Rents and the Leases have not been heretofore sold,
assigned, transferred or set over by any instrument now in force and will not at
any time during the life of this assignment be sold, assigned, transferred or
set over by Mortgagor or by any person or persons whomsoever; and Mortgagor has
good right to sell, assign, transfer and see over the same and to grant to and
confer upon Mortgagee the rights, interest, powers and authorities herein
granted and conferred. Failure of Mortgagee at any time or from time to time to
enforce the assignment of Rents and Leases under this Section shall not in any
manner prevent its subsequent enforcement, and Mortgagee is not obligated to
collect anything hereunder, but is accountable only for sums actually collected.

         8.2 FURTHER ASSIGNMENTS. Mortgagor shall give Mortgagee at any time
upon demand any further or additional forms of assignment or transfer of such
Rents, Leases ant security as may be reasonably requested by Mortgagee, and
shall deliver to Mortgagee executed copies of all such Leases and security.

         8.3 APPLICATION OF RENTS. Mortgagee shall be entitled to deduct and
retain a just and reasonable compensation from monies received hereunder for
its services or that of its agents in collecting such monies. Any monies
received by Mortgagee hereunder may be applied when received from time to time
in payment of any taxes, assessments or other liens affecting the Property
regardless of the delinquency, such application to be in such order as Mortgagee
may determine. The acceptance of this Mortgage by Mortgagee or the exercise of
any rights by it hereunder shall not be, or be construed to be, an affirmation
by it of any Lease nor an assumption of any liability under any Lease.

         8.4 COLLECTION OF RENTS. Upon or at any time after an Event of Default
shall have occurred and be continuing, Mortgagee may declare all sums secured
hereby immediately due and payable, and may, at its option, without notice, and
whether or not the Secured Obligations shall have been declared due and payable,
either in person or by agent, with or without bringing any action or proceeding,
or by a receiver to be appointed by a court, (a) enter upon, take possession of,
manage and operate the Property, or any part thereof (including without
limitation making necessary repairs, alterations and improvements to the
Property); (b) make, cancel, enforce or modify Leases; (c) obtain and evict
tenants; (d) fix or modify Rents; (e) do any acts which Mortgagee deems
reasonably proper to protect the security thereof; and (f) either with or
without taking possession of the Property, in its own name sue for or otherwise
collect and receive such Rents, including those past due and unpaid. In
connection with the foregoing, Mortgagee shall be entitled and empowered to
employ attorneys, and management, rental and other agents in and about the
Property and to effect the matters which Mortgagee is

                                       32
<PAGE>

empowered to do, and in the event Mortgagee shall itself effect such matters,
Mortgagee shall be entitled to charge and receive reasonable management, rental
and other fees therefor as may be customary for comparable properties in the
area in which the Property is located; and the reasonable fees, charges, costs
and expenses of Mortgagee or such persons shall be additional Secured
Obligations. Mortgagee may apply all funds collected as aforesaid, less costs
and expenses of operation and collection, including reasonable attorneys' and
agents' fees, charges, costs and expenses, as aforesaid, upon any Secured
Obligations, and in such order as Mortgagee may determine. The entering upon and
taking possession of the Property, the collection of such Rents and the
application thereof as aforesaid shall not cure or waive any default or waive,
modify or affect notice of default under the Note or this Mortgage or invalidate
any act done pursuant So such notice.

         8.5 AUTHORITY OF MORTGAGEE. Any tenants or occupants of any part of the
Property are hereby authorized to recognize the claims of Mortgagee hereunder
without investigating the reason for any action taken by Mortgagee, or the
validity or the amount of secured obligations owing to Mortgagee, or the
existence of any default in the Note or this Mortgage, or under or by reason of
this assignment of Rents and Leases, or the application to be made by Mortgagee
of any amounts to be paid to Mortgagee. The sole signature of Mortgagee shall be
sufficient for the exercise of any rights under this assignment and the sole
receipt of Mortgagee for any sums received shall be a full discharge and release
therefor to any such tenant or occupant of the Property. Checks for all or any
part of the rentals collected under this assignment of Rents and Leases shall be
drawn to the exclusive order of Mortgagee.

         8.6 INDEMNIFICATION OF MORTGAGEE. Nothing herein contained shall be
deemed to obligate Mortgagee to perform or discharge any obligation, duty or
liability of any lessor under any Lease of the Property, and Mortgagor shall and
does hereby indemnify and hold Mortgagee harmless from any and all liability,
loss or damage which Mortgagee may or might incur under any Lease or by reason
of the assignment; and any and all such liability, loss or damage incurred by
Mortgagee, together with the costs and expenses, including reasonable attorneys'
fees, incurred by Mortgagee in defense of any claims or demands therefor
(whether successful or not), shall be additional Secured Obligations, and
Mortgagor shall reimburse Mortgagee therefor on demand.

                                    ARTICLE 9
                            MISCELLANEOUS PROVISIONS

         9.1 TIME OF THE ESSENCE. Time is of the essence with respect to all
provisions of the Lean Documents.

         9.2 JOINT AND SEVERAL OBLIGATIONS. If Mortgagor is more than one person
or entity, then (a) all persons or entities comprising Mortgagor are jointly and
severally liable for all of the Secured Obligations; (b) all representations,
warranties, and covenants made by Mortgagor shall be deemed representations,
warranties, and covenants of each of the persons or entities comprising
Mortgagor; (c) any breach, Default or Event of Default by any of the persons or
entities comprising Mortgagor hereunder shall be deemed to be a breach, Default,
or Event of Default of Mortgagor; (d) any reference herein contained to the
knowledge or awareness of Mortgagor shall mean the knowledge or awareness of any
of the persons or entities comprising

                                       33
<PAGE>

Mortgagor; and (e) any event creating personal liability of any of the persons
or entities comprising Mortgagor shall create personal liability for all such
persons or entities.

         9.3 WAIVER OF HOMESTEAD AND OTHER EXEMPTIONS. To the extent permitted
by law, Mortgagor hereby waives all rights to any homestead or other exemption
to which Mortgagor would otherwise be entitled under any present or future
constitutional, statutory, or other provision of applicable state or federal
law. Mortgagor hereby waives any right it may have to require Mortgagee to
marshal all or any portion of the security for the Secured Obligations.

         9.4 NON-RECOURSE; EXCEPTIONS TO NON-RECOURSE. Except as expressly set
forth in the Note, the recourse of Mortgagee with respect to the obligations
evidenced by the Note and the other Loan Documents shall be solely to the
Property, Chattels and Intangible Personalty, and any other collateral given as
security for the Note.

         9.5 RIGHTS AND REMEDIES CUMULATIVE. Mortgagee's rights and remedies
under each of the Loan Documents are cumulative of the rights and remedies
available to Mortgagee under each of the other Loan Documents and those
otherwise available to Mortgagee at law or in equity. No act of Mortgagee shall
be construed as an election to proceed under any particular provision of any
Loan Document to the exclusion of any other provision in the same or any other
Loan Document, or as an election of remedies to the exclusion of any other
remedy which may then or thereafter be available to Mortgagee.

         9.6 NO IMPLIED WAIVERS. Mortgagee shall not be deemed to have waived
any provision of any Loan Document unless such waiver is in writing and is
signed by Mortgagee. Without limiting the generality of the preceding sentence,
neither Mortgagee's acceptance of any payment with knowledge of a Default by
Mortgagor, nor any failure by Mortgagee to exercise any remedy following a
Default by Mortgagor shall be deemed a waiver of such Default, and no waiver by
Mortgagee of any particular Default on the part of Mortgagor shall be deemed a
waiver of any other Default or of any similar Default in the future.

         9.7 NO THIRD-PARTY RIGHTS. No person shall be a third-party Mortgagee
of any provision of any of the Loan Documents. All provisions of the Loan
Documents favoring Mortgagee are intended solely for the benefit of Mortgagee,
and no third party shall be entitled to assume or expect that Mortgagee will not
waive or consent to modification of any such provision in Mortgagee's sole
discretion.

         9.8 PRESERVATION OF LIABILITY AND PRIORITY. Without affecting the
liability of Mortgagor or of any other person (except a person expressly
released in writing) for payment and performance of all of the Secured
Obligations, and without affecting the rights of Mortgagee with respect to any
security not expressly released in writing, and without impairing in any way the
priority of this Mortgage over the interests of any person acquired or first
evidenced by recording subsequent to the recording hereof, Mortgagee may, either
before or after the maturity of the Note, and without notice or consent: (a)
release any person liable for payment or performance of all or any part of the
Secured Obligations; (b) make any agreement altering the terms of payment or
performance of all or any of the Secured Obligations; (c) exercise or refrain
from exercising, or waive, any right or remedy which Mortgagee may have under
any of the

                                       34
<PAGE>

Loan Documents; (d) accept additional security of any kind for any of the
Secured Obligations; or (e) release or otherwise deal with any real or personal
property securing the Secured Obligations. Any person acquiring or recording
evidence of any interest of any nature in the Property, the Chattels, or the
Intangible Personalty shall be deemed, by acquiring such interest or recording
any evidence thereof, to have agreed and consented to any or all such actions by
Mortgagee.

         9.9 SUBROGATION OF MORTGAGEE. Mortgagee shall be subrogated to the lien
of any previous encumbrance discharged with funds advanced by Mortgagee under
the Loan Documents, regardless of whether such previous encumbrance has been
released of record.

         9.18 NOTICES. Any notice required or permitted to be given by Mortgagor
or Mortgagee under this Mortgage shall be in writing and will be deemed given
(a) upon personal delivery, (b) on the first business day after receipted
delivery to a courier service which guarantees next-business-day delivery, or
(c) upon receipt if sent by registered or certified United States mail, postage
prepaid, in any case to the appropriate party at its address set forth below:

                  If to Mortgagor:

                           KS Parcel D, LLC
                           101 Main Street, 18th Floor
                           Cambridge, Massachusetts 02142
                           Attention: Mr. Robert L. Green

                  with copies to:

                           The Lyme Timber Company
                           P.O. Box 266
                           16 On the Common
                           Lyme, New Hampshire 03768
                           Attention: Mr. David M. Roby

                           Lyme Properties LLC
                           23 South Main Street
                           Hanover, New Hampshire 03755
                           Attention: Mr. David E. Clem

                           Piper Rudnick LLP
                           One International Place, 21st Floor
                           Boston, Massachusetts 02110-2600
                           Attention: Daniel A. Taylor, Esq.

                                       35
<PAGE>

                  If to Mortgagee:

                           The Variable Annuity Life Insurance Company
                           c/o AIG Global Investment Corp.
                           1 SunAmerica Center, 38th Floor
                           Century City
                           Los Angeles, California 90067-6022
                           Attention: Director-Mortgage Lending and Real Estate

                  with a copy to:

                           Otten, Johnson, Robinson,
                             Neff & Ragonetti, P.C.
                           950 Seventeenth Street, Suite 1600
                           Denver, Colorado 80202
                           Attention: Mark F. Copertino, Esq.

Either party may change such party's address for notices or copies of notices by
giving notice to the other party in accordance with this Section.

         9.11 DEFEASANCE. Upon payment and performance in full of all of the
Secured Obligations, Mortgagee will execute and deliver to Mortgagor such
documents as may be required to release this Mortgage of record.

         9.12 ILLEGALITY. If any provision of this Mortgage is held to be
illegal, invalid, or unenforceable under present or future laws effective during
the term of this Mortgage, the legality, validity, and enforceability of the
remaining provisions of this Mortgage shall not be affected thereby, and in lieu
of each such illegal, invalid or unenforceable provision there shall be added
automatically as a part of this Mortgage a provision as similar in terms to such
illegal, invalid, or unenforceable provision as may be possible and be legal,
valid, and enforceable. If the rights and liens created by this Mortgage shall
be invalid or unenforceable as to any part of the Secured Obligations, then the
unsecured portion of the Secured Obligations shall be completely paid prior to
the payment of the remaining and secured portion of the Secured Obligations, and
all payments made on the Secured Obligations shall be considered to have been
paid on and applied first to the complete payment of the unsecured portion of
the Secured Obligations.

         9.13 USURY SAVINGS CLAUSE. It is expressly stipulated and agreed to be
the intent of Mortgagee and Mortgagor at all times to comply with the applicable
law governing the highest lawful interest rate. If the applicable law is ever
judicially interpreted so as to render usurious any amount called for under the
Note or under any of the other Loan Documents, or contracted for, charged,
taken, reserved or received with respect to the Loan, or if acceleration of the
maturity of the Note, any prepayment by Mortgagor, or any other circumstance
whatsoever, results in Mortgagor having paid any interest in excess of that
permitted by applicable law, then it is the express intent of Mortgagor and
Mortgagee that all excess amounts theretofore collected by Mortgagee be credited
on the principal balance of the Note (or, at Mortgagee's option, paid over to
Mortgagor), and the provisions of the Note and other Loan Documents immediately
be

                                       36
<PAGE>

deemed reformed and the amounts thereafter collectible hereunder and thereunder
reduced, without the necessity of the execution of any new document, so as to
comply with the applicable law, but so as to permit the recovery of the fullest
amount otherwise called for hereunder and thereunder. The right to accelerate
maturity of the Note does not include the right to accelerate any interest which
has not otherwise accrued on the date of such acceleration, and Mortgagee does
not intend to collect any unearned interest in the event of acceleration. All
sums paid or agreed to be paid to Mortgagee for the use, forbearance or
detention of the Secured Obligations evidenced hereby or by the Note shall, to
the extent permitted by applicable law, be amortized, prorated, allocated and
spread throughout the full term of such Secured Obligations until payment in
full so that the rate or amount of interest on account of such Secured
Obligations does not exceed the maximum rate or amount of interest permitted
under applicable law. The term "applicable law" as used herein shall mean any
federal or state law applicable to the Loan.

         9.14 OBLIGATIONS BINDING UPON MORTGAGOR'S SUCCESSORS. This Mortgage is
binding upon Mortgagor and Mortgagor's successors and assigns, and shall inure
to the benefit of Mortgagee, and its successors and assigns, and the provisions
hereof shall likewise be covenants running with the land. The duties, covenants,
conditions, obligations, and warranties of Mortgagor in this Mortgage shall be
joint and several obligations of Mortgagor and Mortgagor's successors and
assigns.

         9.15 CONSTRUCTION. All pronouns and any variations of pronouns herein
shall be deemed to refer to the masculine, feminine, or neuter, singular or
plural, as the identity of the parties may require. Whenever the terms herein
are singular, the same shall be deemed to mean the plural, as the identity of
the parties or the context requires.

         9.16 ATTORNEYS' FEES. Any reference in this Mortgage to attorneys' or
counsels' fees paid or incurred by Mortgagee shall be deemed to include
reasonable paralegals' fees and reasonable legal assistants' fees. Moreover,
wherever provision is made herein for payment of attorneys' or counsel's fees or
expenses incurred by Mortgagee, such provision shall include but not be limited
to, such fees or expenses incurred in any and all judicial, bankruptcy,
reorganization, administrative, or other proceedings, including appellate
proceedings, whether such fees or expenses arise before proceedings are
commenced, during such proceedings or after entry of a final judgment.

         9.17 WAIVER AND AGREEMENT. MORTGAGOR HEREBY EXPRESSLY WAIVES ANY RIGHT
IT MAY HAVE UNDER APPLICABLE LAW TO PREPAY THE NOTE, IN WHOLE OR IN PART,
WITHOUT PREPAYMENT CHARGE, UPON ACCELERATION OF THE MATURITY DATE OF THE NOTE,
AND AGREES THAT, IF FOR ANY REASON A PREPAYMENT OF ALL OR ANY PART OF THE NOTE
IS MADE, WHETHER VOLUNTARILY OR FOLLOWING ANY ACCELERATION OF THE MATURITY DATE
OF THE NOTE BY MORTGAGEE ON ACCOUNT OF THE OCCURRENCE OF ANY EVENT OF DEFAULT
ARISING FOR ANY REASON, INCLUDING, WITHOUT LIMITATION, AS A RESULT OF ANY
PROHIBITED OR RESTRICTED TRANSFER, FURTHER ENCUMBRANCE OR DISPOSITION OF THE
PROPERTY OR ANY PART THEREOF SECURING THE NOTE, THEN, EXCEPT AS OTHERWISE SET
FORTH IN THE NOTE OR THE OTHER LOAN DOCUMENTS, MORTGAGOR SHALL BE OBLIGATED TO
PAY, CONCURRENTLY WITH SUCH

                                       37
<PAGE>

PREPAYMENT, THE PREPAYMENT PREMIUM PROVIDED FOR IN THE NOTE. MORTGAGOR HEREBY
DECLARES THAT MORTGAGEE'S AGREEMENT TO MAKE THE LOAN AT THE INTEREST RATE AND
FOR THE TERM SET FORTH IN THE NOTE CONSTITUTES ADEQUATE CONSIDERATION, GIVEN
INDIVIDUAL WEIGHT BY MORTGAGOR, FOR THIS WAIVER AND AGREEMENT.

         9.18 WAIVER OF JURY TRIAL. MORTGAGEE AND MORTGAGOR KNOWINGLY,
IRREVOCABLY, VOLUNTARILY AND INTENTIONALLY WAIVE ANY RIGHT EITHER MAY HAVE TO A
TRIAL BY JURY IN RESPECT OF ANY ACTION, PROCEEDING OR COUNTERCLAIM BASED ON THIS
MORTGAGE, OR ARISING OUT OF, UNDER OR IN CONNECTION WITH THIS MORTGAGE OR ANY
LOAN DOCUMENT, OR ANY COURSE OF CONDUCT, COURSE OF DEALING, STATEMENT (WHETHER
VERBAL OR WRITTEN) OR ACTIONS OF ANY PARTY HERETO OR TO ANY LOAN DOCUMENT. THIS
PROVISION IS A MATERIAL INDUCEMENT FOR MORTGAGEE AND MORTGAGOR TO ENTER INTO THE
LOAN.

         9.19 GOVERNING LAWS. The substantive laws of the Commonwealth of
Massachusetts shall govern the validity, construction, enforcement and
interpretation of this Mortgage.

         9.20 INCONSISTENCY. In the event of any inconsistency between the terms
of the Loan Documents and the terms of that certain First Mortgage Loan
Application between Mortgagor and Mortgagee, as amended, the terms of the Loan
Documents shall govern and control in all respects.

         9.21 INCORPORATION OF ADDENDUM. The "Leasehold Addendum to Mortgage"
attached hereto is hereby incorporated into and made a part of this Mortgage, as
provided in such Leasehold Addendum to Mortgage.

         9.22 STATUTORY CONDITION. This Mortgage is upon the STATUTORY
CONDITION, and upon the further condition that each of the aforementioned
covenants, agreements, representations and warranties shall be kept and duly
performed. If there shall occur a breach of any of such conditions which
constitutes an Event of Default hereunder, or if the entire mortgage debt
becomes due at the option of Mortgagee, the holder hereof shall have the
STATUTORY POWER OF SALE, and, as to the Collateral, all rights and remedies
conferred by the Uniform Commercial Code.

                   [BALANCE OF PAGE INTENTIONALLY LEFT BLANK]

                                       38
<PAGE>

         IN WITNESS WHEREOF, Mortgagor has executed and delivered this Mortgage
under seal as of the date first mentioned above.

                               KS PARCEL D, LLC, a Delaware limited liability
                               company

                               By: Kendall Square, LLC, a Delaware limited
                                   liability company, its manager

                                   By: Lyme Properties LLC, a New Hampshire
                                       limited liability company, its manager

                                       By:/s/ David E. Clem
                                          --------------------------------------
                                       Name: David E. Clem
                                       Title: Manager

                          COMMONWEALTH OF MASSACHUSETTS

COMMONWEALTH OF MASSACHUSETTS       )
                                    ) ss.
COUNTY OF Middle Sex                )                   November 14, 2003

         Then personally appeared the above-named David E. Clem. Manager of Lyme
Properties LLC, a New Hampshire limited liability company, Manager of Kendall
Square, LLC, a Delaware limited liability company, Manager of KS Parcel D, LLC,
a Delaware limited liability company, and acknowledged the foregoing instrument
to be the free act and deed of David E. Clem and such limited liability
companies before me.

                           /s/ Charlene M. Sullivan
                           -----------------------
                           Notary Public
                           Charlene M. Sullivan
                           My commission expires: 10/30/09

<PAGE>

                         LEASEHOLD ADDENDUM TO MORTGAGE

         This Leasehold Addendum to Mortgage ("Addendum") is attached to and
made a part of that certain Mortgage, Security Agreement, Fixture Filing,
Financing Statement Assignment of Leases and Rents (the "Mortgage") executed by
KS Parcel D, LLC, a Delaware limited liability company ("Mortgagor"), for the
benefit of The Variable Annuity Life Insurance Company, a Texas corporation
("Mortgagee"). This Addendum shall constitute a part of the Mortgage and shall
supplement the terms and conditions of the Mortgage. In the event of a conflict
between the terms of the Mortgage and this Addendum, the terms of this Addendum
shall prevail. Unless otherwise defined herein, the capitalized terms used
herein shall have the meanings ascribed to them in the Mortgage. The term
"Mortgage," as such term appears in any of the Loan Documents, shall mean and
refer to the Mortgage, as supplemented by this Addendum, together with all
exhibits.

         1. Granting Clause. The granting language set forth in Section 2.1 of
the Mortgage shall extend to and include, and Mortgagor does hereby grant,
bargain, sell, convey, mortgage and warrant with MORTGAGE COVENANTS unto
Mortgagee the entire right, title and Interest of Mortgagor in and to the
Leasehold Estate (hereinafter defined) demised to Mortgagor pursuant to the
terms and conditions of the Parking Lease (hereinafter defined), together with
any other or greater interest in the Property hereafter acquired by Mortgagor,
including, but not limited to, any fee estate hereafter acquired by Mortgagor in
the land or improvements demised to Mortgagor under the provisions of such
Parking Lease, and the end entire right, title and interest of Mortgagor in, to
and under the Parking Lease. Except for that portion of the Property in which
Mortgagor's interest therein is in the nature of a leasehold estate, the
Mortgage shall be deemed to encumber, and to grant, bargain, sell, convey,
mortgage and warrant with MORTGAGE and COVENANTS to Mortgagee the fee simple
title to the entire Property. As used herein, the term "Parking Lease" shall
mean that certain Parking Lease dated as of July 17, 2002, by and between
Kendall Square, LLC, a Delaware limited liability company ("Kendall Square"), as
lessor, and KS Parcel A/D, LLC, a Delaware limited liability company, as lessee,
a notice of which dated July 17, 2002, was recorded with the Middlesex S.D.
Registry of Deeds on July 19, 2002, as Instrument No. 987 in Book 35927, Page
340, as conveyed by KS Parcel A, LLC, a Delaware limited liability company
(f/k/a KS Parcel A/D, LLC), to Mortgagor, as evidenced by an Amended and
Restated Notice of Lease by and between Kendall Square, as landlord, and
Mortgagor, as tenant, dated as of November 27, 2002, and recorded with said
Middlesex S.D. Registry of Deeds on December 3, 2002, as Instrument No. 1255 in
Book 37245, Page 400, as amended by First Amendment to Lease dated on or about
the date hereof executed by Kendall Square, KS South Garage, LLC, a Delaware
limited liability company ("KS South Garage"), and Mortgagor, as evidenced by a
Second Amended and Restated Notice of Lease executed by Kendall Square, KS South
Garage and Mortgagor, and recorded with said Middlesex S.D. Registry of Deeds
contemporaneously herewith.

         2. Representations and Warranties. Mortgagor hereby represents,
covenants and warrants to Mortgagee that:

                  (a) Mortgagor is the sole owner and holder of the entire
leasehold estate demised pursuant to the Parking Lease (referred to herein as
the "Leasehold Estate") and

                                    Addendum
                                     Page 1
<PAGE>

the entire right, title and interest of the lessee or tenant under the Parking
Lease creating such Leasehold Estate, and such Leasehold Estate and Mortgagor's
interest under such Parking Lease are free and clear of all liens, encumbrances,
security interests and other claims whatsoever, subject only to the Permitted
Exceptions. The foregoing representation shall, as to that portion of the
Property in which Mortgagor's interest therein is in the nature of a leasehold
estate, be deemed to supersede the representation set forth in Section 3.1 (a)
of the Mortgage;

                  (b) the Parking Lease is in full force and effect and
unmodified;

                  (c) all rents (including any additional rents and other
charges) reserved in the Parking Lease have been paid to the extent they were
payable prior to the date hereof;

                  (d) there are no defaults under the Parking Lease by any of
the parties thereto and there are no events or circumstances existing which,
after notice or the passage of time, or both, would constitute a default or an
event of default under such Parking Lease; and

                  (e) Mortgagor has obtained all such consents and approvals to
mortgage, pledge, assign, transfer, grant, bargain, sell, warrant, convey and/or
encumber Mortgagor's interest in and to the Leasehold Estate and/or the Parking
Lease which are required from the landlord or lessor under the Parking Lease,
and Mortgagee is, and at all times will be, free to exercise its rights and
powers pursuant to the Mortgage, including each of the rights set forth in
Article 7 thereof, without any further consent or approval of the landlord or
lessor under such Parking Lease.

         3. Payments. Mortgagor will pay or cause to be paid all rents,
additional rents, taxes, assessments, water rates, sewer rents, and other
charges mentioned in and made payable by the Parking Lease for which provision
has not been made hereinbefore, when and as often as the same shall become due
and payable, and Mortgagor will within ten (10) days following Mortgagee's
request therefor deliver to Mortgagee evidence of such payments.

         4. Performance of Parking Lease. Mortgagor shall timely pay and
perform, in a timely manner, each of its obligations under or in connection with
the Parking Lease, and shall otherwise pay such sums and take such action as
shall be necessary or required in order to maintain the Parking Lease in full
force and effect in accordance with its terms. Mortgagor shall immediately
furnish to Mortgagee copies of any notices given to Mortgagor by the lessor
under the Parking Lease, alleging the default by Mortgagor in the timely payment
or performance of its obligations under such Parking Lease and any subsequent
communication related thereto. Mortgagor shall also promptly furnish to
Mortgagee copies of any notices given to Mortgagor by the lessor under the
Parking Lease, extending the term of the Parking Lease, requiring or demanding
the expenditure of any sum by Mortgagor (or demanding the taking of any action
by Mortgager), or relating to any other material obligation of Mortgagor under
such Parking Lease or any subsequent communication related thereto. Mortgagor
agrees that Mortgagee, in its sole discretion, may advance any sum or take any
action which Mortgagee believes is necessary or required to maintain the Parking
Lease in full force and effect, and all such sums advanced by Mortgagee,
together with all costs and expenses incurred by Mortgagee in connection with
action taken by Mortgagee pursuant to this Section, shall be due and payable by
Mortgagor to Mortgagee upon demand, shall bear interest from the date that is
ten (10) days following demand

                                    Addendum
                                     Page 2
<PAGE>

therefore until paid at the "Default Rate" (as that term is defined in the
Note), and shall be secured by the Mortgage.

         5. No Modification or Cancellation. Mortgagor will neither do nor
neglect to do anything which may cause or permit the termination of the Parking
Lease. Mortgagor will not surrender the Leasehold Estate or its interest in and
to the Parking Lease, nor terminate or cancel or suffer the termination or
cancellation of the Parking Lease, and it will not without the express written
consent of Mortgagee modify, change, supplement, alter or amend the Parking
Lease, either orally or in writing, and as further security for the repayment of
the indebtedness secured hereby and for the performance of the covenants herein
and in the Parking Lease, Mortgagor hereby assigns to Mortgagee all of its
rights, privileges and prerogatives under the Parking Lease to terminate,
cancel, modify, change, supplement, alter or amend the Parking Lease, arid any
such termination, cancellation, modification, change, supplement, alteration or
amendment of the Parking Lease without the prior written consent thereto by
Mortgagee shall be void and of no force and effect. Mortgagor does hereby
expressly release, relinquish and surrender unto Mortgagee all of Mortgagor's
right, power and authority to cancel, surrender, amend, modify or alter in any
way the terms and provisions of the Parking Lease and any attempt on the part of
Mortgagor to exercise any such right without the written authority and consent
thereto of Mortgagee being first had and obtained shall constitute an Event of
Default hereunder and the entire indebtedness secured hereby shall, at the
option of Mortgagee, become due and payable forthwith and without notice.

         The foregoing notwithstanding, so long as there is no Event of Default
hereunder, or in the performance by Mortgagor of any of the terms, covenants and
conditions in the Parking Lease, Mortgagee shall have no right to terminate,
cancel, modify, change, supplement, alter or amend the Parking Lease.

         6. No Subordination. Mortgagor shall not subordinate the Parking Lease
or the Leasehold Estate to any mortgage, Mortgage or other encumbrance of, or
lien on, the fee interest of any owner of the Property. Any such attempted
subordination shall be void and of no force or effect.

         7. Subleases. All subleases entered into by Mortgagor with respect to
all or any portion of the Property (and all existing subleases modified or
amended by Mortgagor) shall provide that if Mortgagee forecloses under this or
any other Mortgage encumbering the Property or enters into a new lease with the
landlord under the Parking Lease, whether pursuant to the provisions for a new
lease contained in such Parking Lease, in any Landlord Estoppel Agreement
executed for the benefit of Mortgagee, or otherwise, the subtenant shall attorn
to Mortgagee or its assignee and the sublease shall remain in full force and
effect in accordance with its terms notwithstanding the termination of such
Parking Lease.

         8. Prepaid Rents; Security Deposits. Mortgagor hereby assigns to
Mortgagee a security interest in any and all prepaid rents and security deposits
and all other security which the landlord under the Parking Lease now or
hereafter holds for the performance of Mortgagor's obligations thereunder.

                                    Addendum
                                     Page 3
<PAGE>

         9. Estoppels. Promptly upon demand by Mortgagee, Mortgagor shall use
reasonable efforts to obtain from the landlord under the Parking Lease and
furnish to Mortgagee an estoppel certificate of such landlord stating the date
through which rent has been paid, whether or net there are any defaults under
the Parking Lease, the specific nature of any claimed defaults, and such other
matters as may be reasonably requested by Mortgagee.

         10. No Waiver. Mortgagor will not waive, excuse, condone or in any way
release or discharge the landlord under the Parking Lease of or from the
obligations, covenants and agreements by said landlord to be done and performed
under the Parking Lease.

         11. Arbitration; Appraisal and Legal Proceedings. Mortgagor shall
notify Mortgagee of any arbitration, appraisal or legal proceedings involving
obligations under the Parking Lease, and Mortgagee may intervene in any such
proceeding and be made a party. Mortgagor shall promptly provide Mortgagee with
a copy of any decision rendered in any such proceeding.

         12. Default Under or Termination of Parking Lease; Performance by
Mortgagee. The occurrence of any default, after the expiration of any notice,
grace and cure periods, by Mortgagor under the Parking Lease, or the termination
of the Parking Lease before the expiration of the term thereof for any reason,
without the prior written consent of Mortgagee, shall constitute an Event of
Default under the Mortgage and under each of the other Loan Documents. For
purposes of determining whether a default, after the expiration of any notice,
grace and cure periods, has occurred, Mortgagee shall be entitled to rely on,
and accept as correct, any notice of default delivered by the lessor under the
Parking Lease. Mortgagee may (but shall not be obligated to) take any action
Mortgagee deems necessary or desirable to prevent or cure any default by
Mortgagor in the performance of or compliance with any of Mortgagor's covenants
and obligations under the Parking Lease. In such event, the performance by
Mortgagee on behalf of Mortgagor shall not remove or waive, as between Mortgagor
and Mortgagee, the corresponding default under the terms hereof and any amount
advanced and any costs incurred in connection therewith, with interest thereon
at the Default Rate (as defined in the Note) from the date that is ten (10) days
following demand therefor, shall be repayable by Mortgagor without demand and
shall be secured hereby and any such failure aforesaid shall be subject to all
of the rights and remedies of Mortgagee under the Mortgage available on account
of any Event of Default hereunder.

         13. Advances by Mortgagee. To the extent permitted by law, the price
payable by Mortgagor or by any other party so entitled, in the exercise of the
right of redemption, if any, from a sale of the Property due to a foreclosure of
the Mortgage shall include all rents paid and other sums advanced by Mortgagee
on behalf of Mortgagor as the tenant under the Parking Lease.

         14. Merger. So long as any of the indebtedness secured by the Mortgage
shall remain unpaid, unless Mortgagee shall otherwise consent in writing, the
fee title to the Property and the Leasehold Estate shall not merge but shall
always be kept separate and distinct, notwithstanding the union of said estates
either in the landlord or in the tenant, or in a third party, by purchase or
otherwise. Mortgagor further covenants and agrees that, in case Mortgagor shall
acquire the fee title, or any other estate, title or interest in the Property,
the Mortgage shall attach

                                    Addendum
                                     Page 4
<PAGE>

to and cover and be a lien upon such other estate so acquired, and such other
estate so acquired by Mortgagor shall be considered as mortgaged, assigned or
conveyed to Mortgagee and the lien hereof shall cover such estate with the same
force and effect as though specifically herein mortgaged, assigned or conveyed.
The provisions of this Paragraph 14 shall not apply in the event the holder of
the Note secured hereby acquires the fee title to the Property except if
Mortgagee shall so elect.

         15. Rights of Mortgagee. Mortgagee shall have the right at any time
during the term of the Parking Lease to:

                  (a) do any act or thing required of Mortgagor under the
Parking Lease that Mortgagor fails to do, and any act or thing done and
performed by Mortgagee shall be as effective to prevent a forfeiture of
Mortgagor's rights under the Parking Lease as if done by Mortgagor itself; and

                  (b) realize on the security afforded by the Leasehold Estate
by exercising foreclosure proceedings or power of sale or other remedy afforded
at law or in equity, or under the Mortgage, and to:

                           (i) transfer, convey or assign the title of Mortgagor
in the Parking Lease for the estate created by the Parking Lease to any
purchaser at any foreclosure sale, whether the foreclosure sale is conducted
pursuant to court order or pursuant to the power of sale contained in the
Mortgage; and

                           (ii) acquire and succeed to the interest of Mortgagor
under the Parking Lease by virtue of any foreclosure sale, whether the
foreclosure sale is conducted pursuant to court order or pursuant to the power
of sale contained in the Mortgage, or by assignment or deed in lieu of
foreclosure.

         16. Application of Insurance Proceeds and/or Condemnation Awards.
Notwithstanding anything contained in Section 4.5 or 4.8 of the Mortgage to the
contrary, Mortgagee shall have no obligation to apply insurance proceeds and/or
condemnation awards to pay for repairs or replacements necessitated by a
casualty and/or condemnation unless Mortgagor is the party under the Parking
Lease responsible for such repair or replacement.

         17. Bankruptcy Code.

                  (a) Attachment to Right to Remain in Possession. The lien of
the Mortgage shall attach to all of Mortgagor's rights and remedies at any time
arising under or pursuant to Subsection 365(h) of the Bankruptcy Code, 11 U.S.C.
Section 365(h), including, without limitation, all of Mortgagor's rights to
remain in possession of the property, estate and interest conveyed under the
Mortgage.

                  (b) Mortgagor's Election to Treat Parking Lease as Terminated.
Mortgagor shall not without Mortgagee's prior written consent elect to treat the
Parking Lease as terminated under Subsection 365(h)(1) of the Bankruptcy Code,
11 U.S.C. Section 365(h)(1). Any such election made without Mortgagee's consent
shall be void.

                                    Addendum
                                     Page 5
<PAGE>

                  (c) Assignment of Claim for Damages. Mortgagor hereby
unconditionally assigns, transfers and sets over to Mortgagee all of Mortgagor's
claims and rights to the payment of damages arising from any rejection by the
landlord under the Parking Lease (i.e., the fee owner) under the Bankruptcy
Code, 11 U.S.C. Section 101, et seq. Mortgagee shall have the right to proceed
in its own name or in the name of Mortgagor in respect of any claim, suit,
action or proceeding relating to the rejection of the Parking Lease, including,
without limitation, the right to file and prosecute, to the exclusion of
Mortgagor, any proofs of claim, complaints, motions, applications, notices and
other documents, in any case in respect of the landlord under the Parking Lease
under the Bankruptcy Code. This assignment constitutes a present, irrevocable
and unconditional assignment of the foregoing claims, rights and remedies, and
shall continue in effect until all of the indebtedness and obligations secured
by the Mortgage shall have been satisfied and discharged in full. Any amounts
received by Mortgagee as damages arising out of the rejection of the Parking
Lease as aforesaid shall be applied first to all costs and expenses of Mortgagee
(including, without limitation, attorneys' fees) incurred in connection with the
exercise of any of its rights or remedies under this paragraph.

                  (d) Disapproval of Rent Offset. If pursuant to Subsection
365(h)(1)(B) of the Bankruptcy Code, 11 U.S.C. Section 365(h)(1)(B), Mortgagor
shall seek to offset against the rent reserved in the Parking Lease the amount
of any damages caused by the nonperformance by the landlord under the Parking
Lease of any of such landlord's obligations under the Parking Lease after the
rejection by such landlord of the Parking Lease under the Bankruptcy Code,
Mortgagor shall, prior to effecting such offset, notify Mortgagee of its intent
so to do, setting forth the amounts proposed to be so offset and the basis
therefor. Mortgagee shall have the right to object to all or any part of such
offset, and, in the event of such objection, Mortgagor shall not effect any
offset of the amounts so objected to by Mortgagee. If Mortgagee shall have
failed to object as aforesaid within ten (10) days after notice from Mortgagor
in accordance with the first sentence of this paragraph, Mortgagor may proceed
to effect such offset in the amounts set forth in Mortgagor's notice. Neither
Mortgagee's failure to object as aforesaid nor any objection or other
communication between Mortgagee and Mortgagor relating to such offset shall
constitute an approval of any such offset by Mortgagee. Mortgagor shall pay and
protect Mortgagee, and indemnify and save Mortgagee harmless from and against
any and all claims, demands, actions, suits, proceedings, damages, losses, costs
and expenses of every nature whatsoever (including, without limitation,
attorneys' fees) arising from or relating to any offset by Mortgagor against the
rent reserved in the Parking Lease.

                  (e) Control of Litigation. If any action, proceeding, motion
or notice shall be commenced or filed in respect of the landlord under the
Parking Lease or the estate, interest or property conveyed by Mortgagor
hereunder in connection with any case under the Bankruptcy Code, 11 U.S.C.
Section 101, et seq., Mortgagee shall have the option, to the exclusion of
Mortgagor, exercisable upon notice from Mortgagee to Mortgagor, to conduct and
control any such litigation with counsel of Mortgagee's choice. Mortgagee may
proceed in its own name or in the name of Mortgagor in connection with any such
litigation, and Mortgagor agrees to execute any and all powers, authorizations,
consents or other documents required by Mortgagee in connection therewith.
Mortgagor shall, upon demand, pay to Mortgagee all costs and expenses (including
attorneys' fees) paid or incurred by Mortgagee in connection with the
prosecution or conduct of any such proceedings. Any such costs or expenses not
paid by

                                    Addendum
                                     Page 6
<PAGE>

Mortgagor as aforesaid shall be secured by the lien of the Mortgage and shall
be added to the principal amount of the indebtedness secured hereby. Mortgagor
shall not commence any action, suit, proceeding or case, or file any application
or make any motion, in respect of the Parking Lease in any such case under the
Bankruptcy Code without the prior written consent of Mortgagee.

                  (f) Notice of Filing of Petition by or Against the Landlord
Under the Parking Lease. Mortgagor shall, after obtaining knowledge thereof,
promptly notify Mortgagee orally of any filing by or against the landlord under
the Parking Lease of a petition under the Bankruptcy Code, 11 U.S.C. Section
101, et seq., by telephonic notice to the location for Mortgagee stated herein
for notice. Mortgagor shall thereafter forthwith give written notice of such
filing to Mortgagee setting forth any information available to Mortgagor as to
the date of such filing, the court in which such petition was filed and the
relief sought therein. Mortgagor shall promptly deliver to Mortgagee, following
receipt, copies of any and all notices, summonses, pleadings, applications and
other documents received by Mortgagor in connection with any such petition and
any proceedings relating thereto.

                  (g) Mortgagee's Assumption of the Parking Lease. If there
shall be filed by or against Mortgagor a petition under the Bankruptcy Code, 11
U.S.C. Section 101, et seq. and Mortgagor as lessee under the Parking Lease
shall determine to reject the Parking Lease pursuant to Section 365(a) of the
Bankruptcy Code, Mortgagor shall give Mortgagee not less than ten (10) days
prior notice of the date on which Mortgagor shall apply to the Bankruptcy Court
for authority to reject the Parking Lease. Mortgagee shall have the right, but
not the obligation, to serve upon Mortgagor within such ten (10) day period a
notice stating that (i) Mortgagee demands that Mortgagor assume and assign the
Parking Lease to Mortgagee pursuant to Section 365 of the Bankruptcy Code and
(ii) Mortgagee covenants to cure or provide adequate assurance of prompt cure of
all defaults and provide adequate assurance of future performance under the
Parking Lease. If Mortgagee shall serve upon Mortgagor the notice described in
the preceding sentence, Mortgagor shall not seek to reject the Parking Lease and
shall comply with the demand provided for in clause (i) of the preceding
sentence within thirty (30) days after the notice shall have been given subject
to the performance by Mortgagee of the covenant provided for in clause (ii) in
the preceding sentence.

                  (h) Extension of Rejection Period. Effective upon the entry of
an order for relief in respect of Mortgagor under the Bankruptcy Code, 11 U.S.C.
Section 101, et seq., Mortgagor hereby assigns and transfers to Mortgagee a
nonexclusive right to apply to the Bankruptcy Court under Subsection 365(d) of
the Bankruptcy Code for an order extending the period during which the Parking
Lease may be rejected or assumed.

         18. Bankruptcy Code Defined. As used in the Mortgage (i) any reference
to the "Bankruptcy Code" shall be a reference to Title 11 of the United States
Code, as the same may be amended from time to time or any successor statute, and
(ii) any reference to a specific section of Title 11 of the United States Code
shall be a reference to such section, as the same may be amended from time to
time or any successor statute.

         19. Grant of Security Interest. As additional security for the Secured
Obligations, Mortgagor hereby grants to Mortgagee a security interest in all of
Mortgagor's

                                    Addendum
                                     Page 7
<PAGE>

rights and remedies at any time arising under or pursuant to Section 365(h) of
the Bankruptcy Code, or under or pursuant to any other provision of the
Bankruptcy Code, including, without limitation, all of Mortgagor's rights to
remain in possession of any portion of the Property that is subject to a Parking
Lease.

                                    Addendum
                                     Page 8

<PAGE>

                                    EXHIBIT A
                                       TO
                                    MORTGAGE

                               (LEGAL DESCRIPTION)

                                    Exhibit A
                                     Page 1
<PAGE>

                                    EXHIBIT A
                                       TO
                                    MORTGAGE

                               (LEGAL DESCRIPTION)

PARCEL ONE (FEE PARCEL)

A PARCEL OF LAND IN CAMBRIDGE, MIDDLESEX COUNTY, MASSACHUSETTS, WESTERLY OF LAND
NOW OR FORMERLY OF MIRANT KENDALL, L.L.C., SHOWN AS PARCEL D ON A PLAN OF LAND
ENTITLED, "KENDALL SQUARE, SUBDIVISION PLAN OF LAND IN CAMBRIDGE, MASSACHUSETTS,
MIDDLESEX COUNTY", SCALE 1"=50', DATED MAY, 2002, PREPARED BY GUNTHER
ENGINEERING, INC., SHEET 1 OF 6, RECORDED WITH THE MIDDLESEX SOUTH DISTRICT
REGISTRY OF DEEDS ON JULY 19, 2002 IN BOOK 35927, PAGE 209 (PLAN NO. 759 OF
2002), AND MORE PARTICULARLY DESCRIBED AS FOLLOWS:

BEGINNING AT THE NORTHEASTERLY CORNER OF SAID PARCEL, SAID CORNER BEING THE
NORTHWESTERLY CORNER OF LAND NOW OR FORMERLY OF SAID MIRANT KENDALL, L.L.C., AS
SHOWN ON SAID PLAN AND BEING THE POINT OF BEGINNING; THENCE:

S 19-57-30 W      106.39 FEET TO AN IRON PIPE SET; THENCE

N 80-05-01 W      32.09 FEET TO AN IRON PIPE SET; THENCE

S 09-54-59 W      101.62 FEET THE LAST THREE COURSES RUNNING BY THE WESTERLY
                  PROPERTY LINE OF SAID MIRANT KENDALL, L.L.C.; THENCE

N 73-17-11 W      160.73 FEET BY THE NORTHERLY SIDELINE OF KENDALL STREET;
                  THENCE

N 09-54-59 E      187.36 FEET BY THE WESTERLY SIDELINE OF THE NORTH-SOUTH
                  PORTION OF KENDALL STREET; THENCE

S 80-05-01 E      210.24 FEET BY THE SOUTHERLY SIDELINE OF ATHENAEUM STREET
                  TO LAND NOW OR FORMERLY OF SAID MIRANT KENDALL, L.L.C., TO
                  THE POINT OF BEGINNING.

BUT EXCLUDING ANY INTEREST IN THE FEE OF ANY OF THE PRIVATE WAYS SHOWN ON SAID
SUBDIVISION PLAN.

TOGETHER WITH THE BENEFIT OF THE FOLLOWING APPURTENANT EASEMENTS, BUT SUBJECT TO
THE TERMS AND CONDITIONS SET FORTH IN THE GRANT THEREOF:

                                      A-1

<PAGE>

A.       EASEMENTS AS SET FORTH IN KENDALL SQUARE DECLARATION OF COVENANTS,
         EASEMENTS AND RESTRICTIONS DATED AS OF JULY 17, 2002, BY KENDALL
         SQUARE, LLC AND RECORDED ON JULY 19, 2002 AS INSTRUMENT NO. 983 IN BOOK
         35927, PAGE 246;

B.       DEED FROM KENDALL SQUARE, LLC AS GRANTOR AND PARKING GRANTOR, TO KS
         PARCEL A/D, LLC CONVEYING "PARCEL D" DATED AS OF JULY 17, 2002 AND
         RECORDED WITH THE MIDDLESEX S.D. REGISTRY OF DEEDS ON JULY 19, 2002, AS
         INSTRUMENT NO. 985 IN BOOK 35927, PAGE 314.

ALSO KNOWN AS 500 KENDALL STREET, CAMBRIDGE, MASSACHUSETTS.

PARCEL TWO

LEASEHOLD INTEREST ONLY PURSUANT TO THE PARKING LEASE DESCRIBED IN SECTION 1 OF
THE LEASEHOLD ADDENDUM TO THIS MORTGAGE, SECURITY AGREEMENT, FIXTURE FILING,
FINANCING STATEMENT AND ASSIGNMENT OF LEASES AND RENTS.

                                      A-2
<PAGE>

                                    EXHIBIT B
                                       TO
                                    MORTGAGE

                                  (CONTRACTS)

Construction Contract dated September 1, 2000 between Kendall Square LLC and
Turner Construction Company

Architect Contract dated March 1, 2000 between Kendall Square LLC and Behnisch
Behnisch & Partner, Inc.

                                   Exhibit B
                                     Page 1

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