<PAGE>

                                                                   EXHIBIT 10.73

                    LEASE AGREEMENT WITH SYSCO CORPORATION
<PAGE>

--------------------------------------------------------------------------------









                             LEASE AGREEMENT BETWEEN



                 ENCLAVE PARKWAY REALTY, INC., AS LANDLORD, AND



                          SYSCO CORPORATION, AS TENANT



                               DATED JULY 20, 1998











--------------------------------------------------------------------------------
<PAGE>

                                TABLE OF CONTENTS
                                -----------------

<TABLE>
<CAPTION>
                                                                                                               Page
                                                                                                               ----
<S>                                                                                                            <C>
1.       Lease Grant...........................................................................................   1
         -----------

2.       Term..................................................................................................   1
         ----

3.       Rent..................................................................................................   1
         ----
         (a)      Basic Rent...................................................................................   1
                  ----------
         (b)      Payment......................................................................................   1
                  -------
         (c)      Operating Costs..............................................................................   2
                  ---------------
         (d)      Audit........................................................................................   4
                  -----

4.       Delinquent Payment; Handling Charges..................................................................   4
         ------------------------------------

5.       Security Deposit......................................................................................   5
         ----------------

6.       Landlord's Obligations................................................................................   5
         ----------------------
         (a)      Services.....................................................................................   5
                  --------
         (b)      Excess Utility Use...........................................................................   6
                  ------------------
         (c)      Restoration of Services; Abatement...........................................................   6
                  ----------------------------------
         (d)      Special Services.............................................................................   7
                  ----------------

7.       Improvements; Alterations; Repairs; Maintenance.......................................................   8
         -----------------------------------------------
         (a)      Permitted Alterations........................................................................   8
                  ---------------------
         (b)      Improvements; Alterations....................................................................   8
                  -------------------------
         (c)      Repairs; Maintenance.........................................................................   9
                  --------------------
         (d)      Performance of Work..........................................................................   9
                  -------------------
         (e)      Mechanic's Liens.............................................................................   9
                  ----------------

8.       Use...................................................................................................   9
         ---

9.       Assignment and Subletting.............................................................................  10
         -------------------------
         (a)      Transfers to Affiliates......................................................................  10
         (b)      Transfers; Consent...........................................................................  10
                  ------------------
         (c)      Cancellation.................................................................................  11
                  ------------
         (d)      Additional Compensation......................................................................  11
                  -----------------------

10.      Insurance; Waivers; Subrogation; Indemnity............................................................  11
         ------------------------------------------
         (a)      Insurance....................................................................................  11
                  ---------
         (b)      Waiver of Negligence; No Subrogation.........................................................  11
                  ------------------------------------
         (c)      Indemnity....................................................................................  12
                  ---------
         (d)      Self Insurance...............................................................................  12
                  --------------
</TABLE>

                                       i
<PAGE>

<TABLE>
<S>                                                                                                              <C>
11.      Subordination; Attornment; Notice to Landlord's Mortgagee.............................................  12
         ---------------------------------------------------------
         (a)      Subordination................................................................................  12
                  -------------
         (b)      Attornment...................................................................................  12
                  ----------
         (c)      Notice to Landlord's Mortgagee...............................................................  13
                  ------------------------------
         (d)      Landlord's Mortgagee's Protection Provisions.................................................  13
                  --------------------------------------------

12.      Rules and Regulations.................................................................................  13
         ---------------------

13.      Condemnation..........................................................................................  13
         ------------
         (a)      Total Taking.................................................................................  13
                  ------------
         (b)      Partial Taking - Tenant's Rights.............................................................  14
                  --------------------------------
         (c)      Partial Taking - Landlord's Rights...........................................................  14
                  ----------------------------------
         (d)      Award........................................................................................  14
                  -----

14.      Fire or Other Casualty................................................................................  14
         ----------------------
         (a)      Repair Estimate..............................................................................  14
                  ---------------
         (b)      Landlord's and Tenant's Rights...............................................................  14
                  ------------------------------
         (c)      Landlord's Rights............................................................................  14
                  -----------------
         (d)      Repair Obligation............................................................................  15
                  -----------------

15.      Personal Property Taxes...............................................................................  15
         -----------------------

16.      Events of Default.....................................................................................  15
         -----------------

17.      Remedies..............................................................................................  16
         --------

18.      Payment by Tenant; Non-Waiver.........................................................................  17
         -----------------------------
         (a)      Payment by Tenant............................................................................  17
                  -----------------
         (b)      No Waiver....................................................................................  17
                  ---------

19.      Surrender of Premises.................................................................................  17
         ---------------------

20.      Holding Over..........................................................................................  18
         ------------

21.      Certain Rights Reserved by Landlord...................................................................  18
         -----------------------------------

22.      Miscellaneous.........................................................................................  19
         -------------
         (a)      Landlord Transfer............................................................................  19
                  -----------------
         (b)      Landlord's Liability.........................................................................  19
                  --------------------
         (c)      Force Majeure................................................................................  19
                  -------------
         (d)      Brokerage....................................................................................  19
                  ---------
         (e)      Estoppel Certificates........................................................................  19
                  ---------------------
         (f)      Notices......................................................................................  20
                  -------
         (g)      Separability.................................................................................  20
                  ------------
         (h)      Amendments; and Binding Effect...............................................................  20
                  ------------------------------
</TABLE>

                                      ii
<PAGE>

<TABLE>
<S>                                                                                                              <C>
         (i)      Quiet Enjoyment..............................................................................  20
                  ---------------
         (j)      No Merger....................................................................................  20
                  ---------
         (k)      No Offer.....................................................................................  20
                  --------
         (l)      Entire Agreement.............................................................................  20
                  ----------------
         (m)      Governing Law................................................................................  21
                  -------------
         (n)      Joint and Several Liability..................................................................  21
                  ---------------------------
         (o)      Financial Reports............................................................................  21
                  -----------------
         (p)      Landlord's Fees..............................................................................  21
                  ---------------
         (q)      Telecommunications...........................................................................  21
                  ------------------
         (r)      General Definitions..........................................................................  21
                  -------------------
         (s)      Confidentiality..............................................................................  22
                  ---------------
         (t)      Hazardous Materials..........................................................................  22
                  -------------------
         (u)      List of Exhibits.............................................................................  22
                  ----------------

23.      Other Provisions......................................................................................  22
         ----------------

24.      Signage...............................................................................................  23
         -------

25.      Lender Approval.......................................................................................  23
         ---------------

</TABLE>

                                      iii
<PAGE>

                              LIST OF DEFINED TERMS
                              ---------------------

<TABLE>
<CAPTION>
                                                                                                               Page
                                                                                                               ----
<S>                                                                                                            <C>
Lease..........................................................................................................   1
Landlord.......................................................................................................   1
Tenant.........................................................................................................   1
Premises.......................................................................................................   1
Building.......................................................................................................   1
Commencement Date..............................................................................................   1
Term...........................................................................................................   1
Basic Rent.....................................................................................................   1
Rent...........................................................................................................   2
Additional Rent................................................................................................   2
Expense Stop...................................................................................................   2
Operating Costs................................................................................................   2
Taxes..........................................................................................................   3
Operating Costs and Tax Statement..............................................................................   4
Proportionate Share............................................................................................   4
Security Deposit...............................................................................................   5
Permitted Use..................................................................................................   9
Transfer.......................................................................................................  10
Loss...........................................................................................................  11
Landlord's Mortgagee...........................................................................................  12
Taking.........................................................................................................  13
Casualty.......................................................................................................  14
Damage Notice..................................................................................................  14
Event of Default...............................................................................................  15
Laws...........................................................................................................  21
Law............................................................................................................  21
Affiliate......................................................................................................  21
Tenant Party...................................................................................................  21
including......................................................................................................  22
Hazardous Materials............................................................................................  22
Working Drawings............................................................................................... D-1
Work........................................................................................................... D-1
Total Construction Costs....................................................................................... D-2
Construction Allowance......................................................................................... D-2
Parking Area................................................................................................... E-1
</TABLE>

                                      iv
<PAGE>

                                      LEASE
                                      -----


         THIS LEASE AGREEMENT (this "Lease") is entered into as of July 20,
                                     -----
1998, between Enclave Parkway Realty, Inc., a Delaware limited partnership
("Landlord"), and SYSCO Corporation, a Delaware corporation ("Tenant").
  --------                                                    ------

         1. Lease Grant. Subject to the terms of this Lease, Landlord leases to
            -----------
Tenant, and Tenant leases from Landlord, the entirety of Floors 5 and 6 (the
"Premises") as depicted in the plan attached as Exhibit A (and containing the
 --------                                       ---------
stipulated net rentable square feet as set forth in Section 3(c)(7)) in the
office building (the "Building") located at 1430 Enclave Parkway, Houston,
                      --------
Texas. The land on which the Building is located is described on Exhibit B. The
                                                                 ---------
term "Building" includes the related land, driveways, parking facilities, and
      --------
similar improvements.

         2. Term. The term of this Lease shall commence on the earlier of (i)
            ----
October 1, 1998, or (ii) Tenant's occupancy of the Premises (the "Commencement
                                                                  ------------
Date"), and expiring at 5:00 p.m., 120 months from the Commencement Date (the
----
"Term"). If the Commencement Date is not the first day of a calendar month, then
 ----
the Term shall be extended by the number of days between the Commencement Date
and the first day of the next month. Landlord shall deliver the 6th floor of the
Premises to the Tenant on or before August 1, 1998 and shall deliver the 5th
floor of the Premises to Tenant on or before August 15, 1998. If the Premises
are not delivered by Landlord as set forth in the preceding sentence, then (a)
Tenant's obligation to pay Basic Rent and Additional Rent (as defined in Section
3) shall be waived until Landlord tenders possession of the Premises to Tenant,
(b) the Term shall be extended by the time between the scheduled delivery date
and the date on which Landlord tenders possession of the Premises to Tenant, (c)
Landlord shall not be in default hereunder or be liable for damages therefor,
and (d) Tenant shall accept possession of the Premises when Landlord tenders
possession thereof to Tenant. Notwithstanding anything to the contrary contained
herein, if Landlord fails to deliver the Premises to Tenant by August 22, 1998,
then Tenant, as its sole and exclusive remedy, may terminate this Lease.
Landlord and Tenant agree to execute a certificate in the form of Exhibit F to
confirm the Commencement Date.

         3. Rent.
            ----

            (a) Basic Rent. "Basic Rent" (herein so called) shall be the
                ----------   ----------
following amounts for the following periods of time:

         Time Period          Annual Basic Rent             Monthly Basic Rent
         -----------          -----------------             ------------------
          Years 1-5       $20.00 per rentable square            $177,526.67
                          foot/year ($2,130,320)

          Years 6-10      $21.00 per rentable square            $186,403.00
                          foot/year ($2,236,836)


            (b) Payment. Tenant shall timely pay to Landlord Basic Rent and all
                -------
additional sums to be paid by Tenant to Landlord under this Lease (Basic Rent,
Additional Rent, as hereinafter

                                       1
<PAGE>

defined and all other sums required hereunder are collectively referred to as
"Rent"), without deduction or set off, at Landlord's address provided for in
 ----
this Lease or as otherwise specified by Landlord. Basic Rent, adjusted as herein
provided, shall be payable monthly in advance, and shall be accompanied by all
applicable state and local sales or use taxes. The first monthly installment of
Basic Rent shall be payable on or before three (3) business days after the
execution of this Lease; thereafter, Basic Rent shall be payable on the first
day of each month beginning on the first day of the second full calendar month
of the Term. The monthly Basic Rent for any partial month at the beginning of
the Term shall equal the product of 1/365 of the annual Basic Rent in effect
during the partial month and the number of days in the partial month from and
after the Commencement Date, and shall be due on the Commencement Date.

            (c) Operating Costs.
                ---------------

                (1) Subject to the provisions of Paragraph (2) below, Tenant
     shall pay an amount (per each rentable square foot in the Premises)
     ("Additional Rent") equal to its Proportionate Share of the difference
       ---------------
     between the Operating Costs (defined below) for any calendar year after
     calendar year 1998 and the actual Operating Costs for the calendar year
     1998 (the "Expense Stop"). Landlord may make a good faith estimate of the
                ------------
     Additional Rent to be due by Tenant for calendar year 1999 and for any
     calendar year thereafter or part thereof during the Term, and Tenant shall
     pay to Landlord, on or after January 1, 1999, and on the first day of each
     calendar month thereafter, an amount equal to the estimated Additional Rent
     for such calendar year or part thereof divided by the number of months
     therein. From time to time, Landlord may estimate and re-estimate the
     Additional Rent to be due by Tenant and deliver a copy of the estimate or
     re-estimate to Tenant. Thereafter, the monthly installments of Additional
     Rent payable by Tenant shall be appropriately adjusted in accordance with
     the estimations so that, by the end of the calendar year in question,
     Tenant shall have paid all of the Additional Rent as estimated by Landlord.
     Any amounts paid based on such an estimate shall be subject to adjustment
     as herein provided when actual Operating Costs are available for each
     calendar year.

                (2) Notwithstanding anything to the contrary contained herein,
     the Additional Rent due hereunder shall not increase by more than 5% over
     the Additional Rent that was payable in the previous calendar year for
     increases in Operating Costs that are "controllable expenses", such as
     janitorial services, security or maintenance; however, no such limit shall
     apply to non-controllable costs, such as utilities, insurance, charges
     promulgated by government authorities, or any other cost or expense outside
     of the control of Landlord.

                (3) The term "Operating Costs" shall mean all expenses and
                              ---------------
     disbursements (subject to the limitations set forth below) that Landlord
     incurs in connection with the ownership, operation, and maintenance of the
     Building, determined on an annual basis in accordance with generally
     accepted accounting principles consistently applied, including, but not
     limited to, the following costs: (A) wages and salaries (including
     management fees not to exceed 3% of gross revenues attributable to the
     Building) of all employees engaged in the operation, maintenance, and
     security of the Building, including taxes, insurance and benefits relating
     thereto; (B) all supplies and materials used in the

                                       2
<PAGE>

     operation, maintenance, repair, replacement, and security of the Building;
     (C) costs for improvements made to the Building which, although capital in
     nature, are reasonably expected to reduce the normal operating costs of the
     Building, as well as capital improvements made in order to comply with any
     law hereafter promulgated by any governmental authority, as amortized over
     the useful economic life of such improvements as determined by Landlord in
     its reasonable discretion; (D) cost of all utilities, except the cost of
     utilities reimbursable to Landlord by the Building's tenants other than
     pursuant to a provision similar to this Section 3.(c); (E) insurance
     expenses; (F) repairs, replacements, and general maintenance of the
     Building; and (G) service or maintenance contracts with independent
     contractors for the operation, maintenance, repair, replacement, or
     security of the Building (including, without limitation, alarm service,
     window cleaning, and elevator maintenance).

            Operating Costs shall not include costs for (i) capital improvements
     made to the Building, other than capital improvements described in Section
     3.(c)(3)(C) and except for items which are generally considered maintenance
     and repair items, such as painting of common areas, replacement of carpet
     in elevator lobbies, and the like; (ii) repair, replacements and general
     maintenance paid by proceeds of insurance or by Tenant or other third
     parties or reimbursed by warranties of manufacturers, suppliers or
     contractors; (iii) interest, amortization or other payments on loans to
     Landlord; (iv) depreciation; (v) costs, expenses and fees relating to
     solicitation, advertising for and entering into leases for space in the
     Building with any tenants, and leasing commissions in connection therewith;
     (vi) legal expenses for services, other than those that benefit the
     Building tenants generally (e.g., tax disputes); (vii) renovating or
     otherwise improving space for occupants of the Building or vacant space in
     the Building; (viii) Taxes (defined below); (ix) costs in connection with
     services (including electricity) and items or other benefits of a type
     which are not standard for the Building and which are not available to
     Tenant without specific charge therefor, but which are provided to another
     tenant or occupant of the Building, whether or not such other tenant or
     occupant is specifically charged therefor by Landlord; (x) costs of
     sculpture, paintings or works of art; and (xi) federal income taxes imposed
     on or measured by the income of Landlord from the operation of the
     Building. There shall be no offset or credit against Operating Costs for
     any revenue attributable to the parking facilities or any cafeteria or
     vending areas located in the Building.

                (4) Tenant shall also pay its Proportionate Share (defined
     below) of any increase in Taxes for each year and partial year falling
     within the Term, which shall be determined by multiplying the difference
     between (A) the Taxes for the year in question and (B) the Taxes for the
     year 1998 by Tenant's Proportionate Share. Tenant shall pay its
     Proportionate Share of Taxes in the same manner as provided above for
     Additional Rent with regard to Operating Costs. "Taxes" shall mean taxes,
                                                      -----
     assessments, and governmental charges whether federal, state, county or
     municipal, and whether they be by taxing districts or authorities presently
     taxing or by others, subsequently created or otherwise, and any other taxes
     and assessments attributable to the Building (or its operation), excluding,
     however, penalties and interest thereon and federal and state taxes on
     income (if the present method of taxation changes so that in lieu of the
     whole or any part of any Taxes, there is levied on Landlord a capital tax
     directly on the rents received therefrom or a franchise tax, assessment,

                                       3
<PAGE>

     or charge based, in whole or in part, upon such rents for the Building,
     then all such taxes, assessments, or charges, or the part thereof so based,
     shall be deemed to be included within the term "Taxes" for purposes
     hereof). Taxes shall include the costs of consultants retained in an effort
     to lower taxes and all costs incurred in disputing any taxes or in seeking
     to lower the tax valuation of the Building.

                (5) By April 1 of each calendar year, or as soon thereafter as
     practicable, Landlord shall furnish to Tenant a statement of Operating
     Costs for the previous year, adjusted as provided in Section 3.(c)(7), and
     of the Taxes for the previous year (the "Operating Costs and Tax
                                              -----------------------
     Statement"). If the Operating Costs and Tax Statement reveals that Tenant
     ---------
     paid more for Operating Costs than the actual amount for the year for which
     such statement was prepared, or more than its actual share of Taxes for
     such year, then Landlord shall promptly credit or reimburse Tenant for such
     excess without interest; likewise, if Tenant paid less than Tenant's actual
     Proportionate Share of Additional Rent or share of Taxes due, then Tenant
     shall promptly pay Landlord such deficiency without interest.

                (6) As used herein, Tenant's "Proportionate Share" shall be
                                              -------------------
     34.08%, which is the percentage obtained by dividing the rentable square
     feet of area in the Premises, which is stipulated to be 106,516 rentable
     square feet, by the total number of square feet of area in the Building,
     which is stipulated to be 312,564 rentable square feet.

                (7) With respect to any calendar year or partial calendar year
     in which the Building is not occupied to the extent of 95% of the rentable
     area thereof, the Operating Costs for such period shall, for the purposes
     hereof, be increased to the amount which would have been incurred had the
     Building been occupied to the extent of 95% of the rentable area thereof.

            (d) Audit. Upon written notice delivered before the later of July 1
                -----
or sixty (60) days after Tenant receives the Operating Costs and Tax Statement,
Tenant shall have the right to cause an audit to be made of Landlord's
calculations of Additional Rent for the prior calendar year. Such audit shall be
made by Tenant's in house accountants or by a reputable accounting firm of
national standing (in the latter case which are not being compensated for such
service on a contingent or incentive fee basis) and at the expense of Tenant,
and Landlord shall provide access to Landlord's books and records for the
purpose of such audit. If the final results of the audit reflect that an
incorrect amount of Additional Rent has been charged in any calendar year,
Landlord or Tenant, as the case may be, shall reimburse the other party within
30 days of receiving the result of such audit. Notwithstanding the foregoing, if
the final results of the audit reflects in any calendar year the Additional Rent
was overstated by more than five percent (5%), Landlord shall reimburse Tenant
for 50% of the reasonable out of pocket costs incurred by Tenant in connection
with the audit then being conducted by Tenant, but in no case in excess of
$2,500.00

         4. Delinquent Payment; Handling Charges. Landlord may charge Tenant a
            ------------------------------------
fee equal to 5% of the delinquent payment for any past due payments required
hereunder to reimburse Landlord for its cost and inconvenience incurred as a
consequence of Tenant's delinquency. In no event, however, shall the charges
permitted under this Section 4 or elsewhere in this Lease, to the extent they
are considered to be interest under law, exceed the maximum lawful rate of
interest, and

                                       4
<PAGE>

any such payment may, at the election of Landlord be returned to Tenant or
credited against other payments due hereunder.

         5. Security Deposit. In the event that (i) Tenant abandons or vacates
            ----------------
the Premises or fails to continuously operate its business in the Premises for
the Permitted Use, or (ii) any Transfer is made as permitted under Section 9
(other than under Section 9(a)), then Tenant shall pay to Landlord $177,526.67
(the "Security Deposit"), which shall be held by Landlord to secure Tenant's
      ----------------
performance of its obligations under this Lease. The Security Deposit is not an
advance payment of Rent or a measure or limit of Landlord's damages upon an
Event of Default (defined in Section 16). Landlord may, from time to time and
without prejudice to any other remedy, use all or a part of the Security Deposit
to perform any obligation Tenant fails to perform hereunder. Following any such
application of the Security Deposit, Tenant shall pay to Landlord on demand the
amount so applied in order to restore the Security Deposit to its original
amount. Provided that Tenant has performed all of its obligations hereunder,
Landlord shall, within 30 days after the Term ends, return to Tenant the portion
of the Security Deposit which was not applied to satisfy Tenant's obligations.
The Security Deposit may be commingled with other funds, and no interest shall
be paid thereon. If Landlord transfers its interest in the Premises and the
transferee assumes Landlord's obligations under this Lease, then Landlord may
assign the Security Deposit to the transferee and Landlord thereafter shall have
no further liability for the return of the Security Deposit.

         6. Landlord's Obligations.
            ----------------------

            (a) Services. Provided that no Event of Default exists, Landlord
                --------
shall use reasonable commercial efforts to provide the services set forth
herein. Landlord shall furnish to Tenant (1) water at those points of supply
provided for general use of tenants of the Building; (2) heated and refrigerated
air conditioning as appropriate, at such temperatures and in such amounts as are
standard for comparable buildings in the vicinity of the Building; (3)
janitorial service to the Premises on weekdays, other than holidays, for
Building-standard installations and such window washing as may from time to time
be reasonably required; (4) elevators for ingress and egress to the floor on
which the Premises are located, in common with other tenants, provided that
Landlord may reasonably limit the number of operating elevators during
non-business hours and holidays; and (5) electrical current during normal
business hours for equipment that does not require more than 110 volts and whose
electrical energy consumption does not exceed normal office usage. Items (1),
(2) and (4) above shall be provided on a 24 hour basis, seven days per week
except as may be limited in cases of emergency or maintenance (provided that
Landlord shall use reasonable commercial efforts to minimize any interruptions
in services due to, and to notify Tenant in advance of, maintenance
requirements). Landlord shall maintain the common areas of the Building in
reasonably good order and condition. If Tenant desires any of the services
specified in Section 6.(a)(2): (A) at any time other than between 7:00 a.m. and
6:00 p.m. on weekdays or (at the request of Tenant, and without additional cost)
between 8:00 a.m. and 12:00 p.m. on Saturday, or (B) on Sunday or holidays, then
such services shall be supplied to Tenant upon the written request of Tenant
delivered to Landlord before 3:00 p.m. on the business day preceding such extra
usage, and Tenant shall pay to Landlord the greater of (i) $50 per fan hour (2
fans per floor, operated independently) or (ii) Landlord's actual cost of such
services, with such payments being due and payable with the next installment of
Rent that is payable hereunder. The costs incurred by Landlord in providing
after-hour

                                       5
<PAGE>

HVAC service to Tenant shall include costs for electricity, water, sewage, water
treatment, labor, metering, filtering, and maintenance reasonably allocated by
Landlord to providing such service.

            (b) Excess Utility Use. Landlord shall not be required to furnish
                ------------------
electrical current for equipment that requires more than 110 volts or other
equipment whose electrical energy consumption exceeds normal office usage. If
Tenant's requirements for or consumption of electricity exceed the electricity
to be provided by Landlord as described in Section 6.(a), Landlord shall, at
Tenant's expense, make reasonable efforts to supply such service through the
then-existing feeders and risers serving the Building and the Premises, and
Tenant shall pay to Landlord the cost of such service within ten days after
Landlord has delivered to Tenant an invoice therefor. Landlord may determine the
amount of such additional consumption and potential consumption by any
verifiable method, including installation of a separate meter in the Premises
installed, maintained, and read by Landlord, at Tenant's expense. Tenant shall
not install any electrical equipment requiring special wiring or requiring
voltage in excess of 110 volts or otherwise exceeding 0.5 kilowatts per hour per
square foot of net rentable area of the Premises unless approved in advance by
Landlord. Landlord may, at its option, install metering equipment to monitor
Tenant's electrical usage in the Premises, and any excess usage shall be
invoiced, and due within ten days after Landlord has delivered to Tenant an
invoice therefor. The use of electricity in the Premises shall not exceed the
capacity of existing feeders and risers to or wiring in the Premises. Any risers
or wiring required to meet Tenant's excess electrical requirements shall, upon
Tenant's written request, be installed by Landlord, at Tenant's cost, if, in
Landlord's judgment, the same are necessary and shall not cause permanent damage
to the Building or the Premises, cause or create a dangerous or hazardous
condition, entail excessive or unreasonable alterations, repairs, or expenses,
or interfere with or disturb other tenants of the Building. If Tenant uses
machines or equipment in the Premises which affect the temperature otherwise
maintained by the air conditioning system or otherwise overload any utility,
Landlord may install supplemental air conditioning units or other supplemental
equipment in the Premises, and the cost thereof, including the cost of
installation, operation, use, and maintenance, shall be paid by Tenant to
Landlord within ten days after Landlord has delivered to Tenant an invoice
therefor.

            (c) Restoration of Services; Abatement. Landlord shall use
                ----------------------------------
reasonable efforts to restore any service required of it that becomes
unavailable; however, such unavailability shall not render Landlord liable for
any damages caused thereby, be a constructive eviction of Tenant, constitute a
breach of any implied warranty, or, except as provided below, entitle Tenant to
any abatement of Tenant's obligations hereunder. If, however, Tenant is
prevented from using the Premises for more than 15 consecutive business days
because of the unavailability of any such service and such unavailability was
not caused by a Tenant Party, then Tenant shall, as its exclusive remedy be
entitled to a reasonable abatement of Rent for each consecutive day (after such
15-day period) that Tenant is so prevented from using the Premises. If such
interruption continues for more than 15 business days, then Landlord shall
within thirty (30) days after such interruption provide to Tenant a written
report prepared by a contractor or architect located in Houston, Texas selected
jointly by Landlord and Tenant setting forth an estimate of time required to
restore such services. To the extent such interruption is not capable of being
cured by Landlord (in the opinion of the contractor or architect) within 180
days (or if such interruption is due to Tenant's negligence or wilful
misconduct, and is not capable of being cured by Landlord (in the opinion of the
contractor or architect) within 210 days), then Tenant, at its option may, in
addition to the remedies set forth

                                       6
<PAGE>

in the preceding sentence terminate this Lease and all of its obligations for
the remaining balance of the Term of this Lease with respect only to the portion
of the Premises so affected by such interruption and non-use by giving written
notice of such termination to Landlord within thirty (30) days after receipt of
the opinion of the contractor or architect that the interruption can not be
cured by Landlord within the time period set forth above. Failure to give such
notice within such periods shall be deemed to be a waiver thereof by Tenant for
all purposes. If Tenant shall elect to terminate this Lease as provided above,
the Basic Rent and any and all other Rent payable by Tenant to Landlord
hereunder shall be apportioned and paid up to the date of such termination,
except as otherwise abated as permitted under the terms hereof but not
otherwise.

            (d)   Special Services.
                  ----------------

            (i)   Tenant shall have the right, subject to availability, to use
                  the area of the Building currently used as a vending and
                  employee lunch area, on a non-exclusive basis in conjunction
                  with the use of other tenants in the Building; however,
                  Landlord reserves the right to change the nature or use of the
                  area now used for such purposes.

            (ii)  Landlord shall, upon reasonable approval of Tenant's plans and
                  specifications, allow Tenant to connect its systems to the
                  backup generators located at the Building. Tenant's use of
                  power from the backup generators is subject to the following:
                  The backup generators of the Building provide emergency power
                  to all Building systems on a priority basis. As generator
                  capacity becomes available, the system begins loading the
                  critical load groups in order of priority. The system will not
                  add load unless generator capacity is available. Those
                  Building systems receiving priority in order of their
                  importance are fire and life safety systems, elevator systems
                  chilled water and building automation systems and UPS
                  (uninterruptible power supply) power. Tenant acknowledges that
                  in the event of an emergency, the backup generators may be
                  required to shed noncritical loads servicing standard Building
                  systems e.g., lighting to office space and common areas,
                          ----
                  power to the vending machine area, components of the
                  transportation systems and other Building systems.

            (iii) Certain space on the first floor of the Building is currently
                  leased to another tenant of the Building; however, said space
                  may be generally available for conference room usage. To the
                  extent said space is available, Landlord shall coordinate the
                  availability of said space and will use reasonable commercial
                  efforts to make said space available from time to time, upon
                  prior request for Tenant's usage, subject to such limitations
                  as the existing tenant, and any other tenant's usage of said
                  space may require.

            (iv)  Landlord agrees to allocate up to 100 square feet of space on
                  the first floor of the Building for a reception area for
                  Tenant, and cooperate with Tenant in the design and
                  construction of said reception area, at Tenant's sole cost and
                  expense. At the end of the Term, Tenant shall remove all items
                  constructed

                                       7
<PAGE>

                  in accordance herewith from the first floor of the Building,
                  and restore the portion so affected to the pre-existing
                  condition.

         7. Improvements; Alterations; Repairs; Maintenance.
            -----------------------------------------------

            (a)   Permitted Alterations. Except for (i) the initial leasehold
                  ---------------------
improvements in accordance with the Work Letter attached as Exhibit D (the "Work
                                                            ---------       ----
Letter"), (ii) any alteration that costs less than $25,000, and (iii) any
------
alteration involving carpeting, painting or wallpaper, Tenant shall make no
alterations, installations, additions, or improvements in or to the Premises
without Landlord's prior written consent that:

            (x)   would be visible from outside the Premises (other than from
                  elevator cab openings of each Floor); or

            (y)   would materially affect the Building's mechanical, electrical,
                  plumbing, security or life safety systems; or

            (z)   are structural in nature.

                  (b)  Improvements; Alterations. Except as set forth in
                       -------------------------
                       Paragraph 7(a):

            (i)   Improvements to the Premises shall be installed at Tenant's
                  expense only in accordance with plans and specifications which
                  have been previously submitted to and approved in writing by
                  Landlord. No alterations or physical additions in or to the
                  Premises may be made without Landlord's prior written consent,
                  which shall not be unreasonably withheld or delayed; however,
                  Landlord may withhold its consent to any alteration or
                  addition that would be visible from outside the Premises or
                  affect the Building's structure or its HVAC, plumbing,
                  electrical, security, life support or mechanical systems.

            (ii)  Tenant shall not paint or install lighting or decorations,
                  signs, window or door lettering, or advertising media of any
                  type on or about the Premises without the prior written
                  consent of Landlord, which shall not be unreasonably withheld
                  or delayed; however, Landlord may withhold its consent to any
                  such painting or installation which would affect the
                  appearance of the exterior of the Building or of any common
                  areas of the Building. All alterations, additions, or
                  improvements (specifically including any cabling,
                  telecommunications lines or other conduit) made in or upon the
                  Premises shall, at Landlord's option, either be removed by
                  Tenant prior to the end of the Term (and Tenant shall repair
                  all damage caused thereby), or shall remain on the Premises at
                  the end of the Term without compensation to Tenant.

            All alterations, additions, and improvements shall be constructed,
maintained, and used by Tenant, at its risk and expense, in accordance with all
Laws; Landlord's approval of the

                                       8
<PAGE>

plans and specifications therefor shall not be a representation by Landlord that
such alterations, additions, or improvements comply with any Law.

            (c)   Repairs; Maintenance. Tenant shall maintain the Premises
                  --------------------
in a clean, safe, and operable condition, and shall not permit or allow to
remain any waste or damage to any portion of the Premises. Tenant shall repair
or replace, subject to Landlord's direction and supervision, any damage to the
Building caused by a Tenant Party. If Tenant fails to make such repairs or
replacements within 15 days after the occurrence of such damage, then Landlord
may make the same at Tenant's cost upon written notice to Tenant. If any such
damage occurs outside of the Premises, then Landlord may elect to repair such
damage at Tenant's expense, rather than having Tenant repair such damage. The
cost of all repair or replacement work performed by Landlord under this Section
7 shall be paid by Tenant to Landlord within ten days after Landlord has
invoiced Tenant therefor.

            (d)   Performance of Work. All work described in this Section 7
                  -------------------
shall be performed only by Landlord or by contractors and subcontractors
approved in writing by Landlord. Tenant shall cause all contractors and
subcontractors to procure and maintain insurance coverage naming Landlord as an
additional insured against such risks, in such amounts, and with such companies
as Landlord may reasonably require. All such work shall be performed in
accordance with all Laws and in a good and workmanlike manner so as not to
damage the Premises, the Building, or the components thereof.

            (e)   Mechanic's Liens. Tenant shall not permit any mechanic's liens
                  ----------------
to be filed against the Premises or the Building for any work performed,
materials furnished, or obligation incurred by or at the request of Tenant. If
such a lien is filed, then Tenant shall, within ten days after Landlord has
delivered notice of the filing thereof to Tenant, either pay the amount of the
lien or diligently contest such lien and deliver to Landlord a bond or other
security reasonably satisfactory to Landlord. If Tenant fails to timely take
either such action, then Landlord may pay the lien claim, and any amounts so
paid, including expenses and interest, shall be paid by Tenant to Landlord
within ten days after Landlord has invoiced Tenant therefor.

         8. Use. Tenant shall continuously occupy and use the Premises only for
            ---
general office, administration, systems and related telecommunications purposes
(the "Permitted Use") and shall comply with all Laws relating to the use,
      -------------
condition, access to, and occupancy of the Premises. The Premises shall not be
used for any use which is disreputable, creates extraordinary fire hazards, or
results in an increased rate of insurance on the Building or its contents, or
for the storage of any hazardous materials or substances. If, because of a
Tenant Party's acts, the rate of insurance on the Building or its contents
increases, then such acts shall be an Event of Default, Tenant shall pay to
Landlord the amount of such increase on demand, and acceptance of such payment
shall not waive any of Landlord's other rights. Tenant shall conduct its
business and control each other Tenant Party so as not to create any nuisance or
unreasonably interfere with other tenants or Landlord in its management of the
Building.

                                       9
<PAGE>

         9. Assignment and Subletting.
            -------------------------

            (a) Transfers to Affiliates. Tenant shall have the right, without
                -----------------------
the consent of Landlord, to assign this Lease, in whole but not in part, or
sublease the Premises or any portion thereof, or to permit the occupancy of any
portion of Premises, only to an Affiliate of Tenant, including any successor
entity by merger, consolidation, liquidation, reorganization or otherwise or any
entity acquiring all or substantially all of the assets of Tenant, whether or
not there may be a change in Tenant's name. Tenant shall promptly give Landlord
notice and provide Landlord such documentation as Landlord may reasonably
request for any transaction described in this Section 9(a).

            (b) Transfers; Consent. Except as allowed under Section 9(a), Tenant
                ------------------
shall not, without the prior written consent of Landlord, (1) assign, transfer,
or encumber this Lease or any estate or interest herein, whether directly or by
operation of law, (2) permit any other entity to become Tenant hereunder by
merger, consolidation, or other reorganization, (3) if Tenant is an entity other
than a corporation whose stock is publicly traded, permit the transfer of an
ownership interest in Tenant so as to result in a change in the current control
of Tenant, (4) sublet any portion of the Premises, (5) grant any license,
concession, or other right of occupancy of any portion of the Premises, or (6)
permit the use of the Premises by any parties other than Tenant (any of the
events listed in Section 9.(b)(1) through 9.(b)(6) being a "Transfer"). If
                                                            --------
Tenant requests Landlord's consent to a Transfer, then Tenant shall provide
Landlord with executed documentation of the proposed Transfer, and the following
information about the proposed transferee: name and address; reasonably
satisfactory information about its business and business history; its proposed
use of the Premises; banking, financial, and other credit information; and
general references sufficient to enable Landlord to determine the proposed
transferee's creditworthiness and character. Landlord shall not unreasonably
withhold its consent to any assignment or subletting of the Premises, provided
that the proposed transferee (A) is creditworthy, (B) has a good reputation in
the business community, (C) does not engage in business similar to those of the
Landlord, any affiliate of the Landlord, or of other tenants in the Building,
and (D) is not another occupant of the Building or person or entity with whom
Landlord is negotiating to lease space in the Building; otherwise, Landlord may
withhold its consent in its sole discretion. Tenant shall (i) reimburse Landlord
immediately upon request for its reasonable attorneys' fees incurred in
connection with considering any request for consent to a Transfer, and (ii)
shall provide Landlord with the Security Deposit required under Section 5 upon
Landlord consenting to such transfer. If Landlord consents to a proposed
Transfer, then the proposed transferee shall deliver to Landlord a written
agreement whereby it expressly assumes Tenant's obligations hereunder; however,
any transferee of less than all of the space in the Premises shall be liable
only for obligations under this Lease that are properly allocable to the space
subject to the Transfer for the period of the Transfer. No Transfer shall
release Tenant from its obligations under this Lease, but rather Tenant and its
transferee shall be jointly and severally liable therefor. Landlord's consent to
any Transfer shall not waive Landlord's rights as to any subsequent Transfers.
If an Event of Default occurs while the Premises or any part thereof are subject
to a Transfer, then Landlord, in addition to its other remedies, may collect
(and retain) directly from such transferee all rents becoming due to Tenant.
Tenant authorizes its transferees to make payments of rent directly to Landlord
upon receipt of notice from Landlord to do so. Tenant shall pay for the cost of
any demising walls or other improvements necessitated by a proposed subletting
or assignment.

                                      10
<PAGE>

          (c)  Cancellation. Landlord may, within 30 days after submission of
               ------------
Tenant's written request for Landlord's consent to an assignment or subletting,
cancel this Lease as to the portion of the Premises proposed to be sublet or
assigned as of the date the proposed Transfer is to be effective. If Landlord
cancels this Lease as to any portion of the Premises, then this Lease shall
cease for such portion of the Premises and Tenant shall pay to Landlord all Rent
accrued through the cancellation date relating to the portion of the Premises
covered by the proposed Transfer. Thereafter, Landlord may lease such portion of
the Premises to the prospective transferee (or to any other person) without
liability to Tenant.

          (d)  Additional Compensation. Tenant shall pay to Landlord,
               -----------------------
immediately upon receipt thereof, 75% of the excess (if any) of (1) all
compensation received by Tenant for a Transfer less the costs reasonably
incurred by Tenant with unaffiliated third parties in connection with such
Transfer (i.e., brokerage commissions, tenant finish work, and the like) over
(2) the Rent allocable to the portion of the Premises covered thereby.

     10.  Insurance; Waivers; Subrogation; Indemnity.
          ------------------------------------------

          (a)  Insurance.  Tenant shall maintain throughout the Term the
               ---------
following insurance policies: (1) commercial general liability insurance in
amounts of $5,000,000 per occurrence or such other amounts as Landlord may from
time to time reasonably require, insuring Tenant, Landlord, Landlord's agents
and their respective affiliates against all liability for injury to or death of
a person or persons or damage to property arising from the use and occupancy of
the Premises (except for the gross negligence or willful misconduct of Landlord
or Landlord's agents and their respective affiliates), (2) insurance covering
the full value of Tenant's property and improvements, and other property
(including property of others) in the Premises, (3) contractual liability
insurance sufficient to cover Tenant's indemnity obligations hereunder, (4)
worker's compensation insurance, containing a waiver of subrogation endorsement
acceptable to Landlord, and (5) business interruption insurance. Except as set
forth in Section 10(b) Tenant's insurance shall provide primary coverage to
Landlord when any policy issued to Landlord provides duplicate or similar
coverage, and in such circumstance Landlord's policy will be excess over
Tenant's policy. Tenant shall furnish to Landlord certificates of such insurance
and such other evidence satisfactory to Landlord of the maintenance of all
insurance coverages required hereunder, and Tenant shall obtain a written
obligation on the part of each insurance company to notify Landlord at least 30
days before cancellation or a material change of any such insurance policies.
All such insurance policies shall be in form, and issued by reputable companies
rated by A.M. Best (or similar service) in one of the three highest ratings
categories.

          (b)  Waiver of Negligence; No Subrogation.  Landlord and Tenant each
               ------------------------------------
waives any claim it might have against the other for any injury to or death of
any person or persons or damage to or theft, destruction, loss, or loss of use
of any property (a "Loss"), to the extent the same is insured against under any
                    ----
insurance policy that covers the Building, the Premises, Landlord's or Tenant's
fixtures, personal property, leasehold improvements, or business, or, in the
case of Tenant's waiver, is required to be insured against under the terms
hereof, regardless of whether the negligence of the other party caused such
Loss; however, Landlord's waiver shall not include any deductible amounts on
insurance policies carried by Landlord. Each party shall cause its insurance

                                      11
<PAGE>

carrier to endorse all applicable policies waiving the carrier's rights of
recovery under subrogation or otherwise against the other party.

          (c)  Indemnity. Subject to Section 10(b), Tenant shall indemnify and
               ---------
save harmless Landlord and its agents, servants, directors, officers, invitees,
partners, venturers, contractors, lenders under security documents, and
employees from and against any and all liabilities, claims, costs (including,
but not limited to, court costs, reasonable attorneys' fees, and costs of
investigation), and actions of any kind arising or alleged to arise by reason of
injury to or death of any person or damage to or loss of property occurring on,
in, or about the Premises or Building (by reason of any other claim of whatever
nature of any person or party related to the Premises or the Building (including
other tenants in the Building)); in each case, to the extent caused by Tenant's
failure to perform its obligations under this Lease or the negligence, gross
negligence or wilful misconduct of Tenant or any employee, director, officer,
servant, or agent to the extent Tenant is under the law responsible for the
actions of such persons. The previous sentence shall not apply to Hazardous
Materials, which are subject to a separate indemnity provision in Section 22(t).
This indemnity provision shall survive termination or expiration of this Lease.
If any proceeding is filed for which indemnity is required hereunder, Tenant
agrees, upon request therefor, to defend the indemnified party in such
proceeding at its sole cost utilizing counsel satisfactory to the indemnified
party.

          (d)  Self Insurance.  Notwithstanding the foregoing, Tenant may
               --------------
maintain a program of self-insurance or captive insurance covering all or any
portion of the insurance required hereby so long as SYSCO Corporation and/or an
Affiliate of SYSCO Corporation, is the Tenant hereunder, or is liable for the
obligations of Tenant hereunder, and SYSCO Corporation (or the Affiliate that is
liable for the obligation of Tenant) maintains a net worth according to
generally accepted accounting principles of at least $250,000,000.

     11.  Subordination; Attornment; Notice to Landlord's Mortgagee.
          ---------------------------------------------------------

          (a)  Subordination.  This Lease shall be subordinate to any deed of
               -------------
trust, mortgage, or other security instrument, or any ground lease, master
lease, or primary lease, that now or hereafter covers all or any part of the
Premises (the mortgagee under any such mortgage or the lessor under any such
lease is referred to herein as a "Landlord's Mortgagee") provided, as a
                                  --------------------
condition precedent to such subordination, Landlord agrees to take commercially
reasonable actions (including obtaining written documentation from Landlord's
Mortgagee reasonably acceptable to Landlord, Tenant and Landlord's Mortgagee) to
assure that each such mortgagee shall expressly covenant, or each such mortgage
shall expressly provide, that so long as Tenant is not in default under this
Lease, Tenant's quiet possession of the Premises shall remain undisturbed, on
the terms, covenants and conditions stated herein, whether or not the mortgage
is in default and notwithstanding any foreclosure or other action brought by
Landlord's Mortgagee. Any Landlord's Mortgagee may elect, at any time,
unilaterally, to make this Lease superior to its mortgage, ground lease, or
other interest in the Premises by so notifying Tenant in writing.

          (b)  Attornment. Tenant shall attorn to any party succeeding to
               ----------
Landlord's interest in the Premises, whether by purchase, foreclosure, deed in
lieu of foreclosure, power of sale,

                                      12
<PAGE>

termination of lease, or otherwise, upon such party's request, and shall execute
such agreements confirming such attornment as such party may reasonably request.

          (c)  Notice to Landlord's Mortgagee. Tenant shall not seek to enforce
               ------------------------------
any remedy it may have for any default on the part of Landlord without first
giving written notice by certified mail, return receipt requested, specifying
the default in reasonable detail, to any Landlord's Mortgagee whose address has
been given to Tenant, and affording such Landlord's Mortgagee a reasonable
opportunity to perform Landlord's obligations hereunder.

          (d)  Landlord's Mortgagee's Protection Provisions. If Landlord's
               ---------------------------------------------
Mortgagee shall succeed to the interest of Landlord under this Lease, Landlord's
Mortgagee shall not be: (1) liable for any act or omission of any prior lessor
(including Landlord); (2) bound by any rent or additional rent or advance rent
which Tenant might have paid for more than the current month to any prior lessor
(including Landlord), and all such rent shall remain due and owing,
notwithstanding such advance payment; (3) bound by any termination, amendment or
modification of this Lease made without Landlord's Mortgagee's consent and
written approval, except for those terminations, amendments and modifications
permitted to be made by Landlord without Landlord's Mortgagee's consent pursuant
to the terms of the loan documents between Landlord and Landlord's Mortgagee;
(4) subject to the defenses which Tenant might have against any prior lessor
(including Landlord); and (5) subject to the offsets which Tenant might have
against any prior lessor (including Landlord) except for those offset rights
which (A) are expressly provided in this Lease, (B) relate to periods of time
following the acquisition of the Building by Landlord's Mortgagee, and (C)
Tenant has provided written notice to Landlord's Mortgagee and provided
Landlord's Mortgagee a reasonable opportunity to cure the event giving rise to
such offset event. Landlord's Mortgagee shall have no liability or
responsibility under or pursuant to the terms of this Lease or otherwise after
it ceases to own an interest in the Building. Nothing in this Lease shall be
construed to require Landlord's Mortgagee to see to the application of the
proceeds of any loan, and Tenant's agreements set forth herein shall not be
impaired on account of any modification of the documents evidencing and securing
any loan.

     12.  Rules and Regulations. Tenant shall comply with the rules and
          ---------------------
regulations of the Building which are attached hereto as Exhibit C, except to
                                                         ---------
the extent that any such rules and regulations conflict with the terms of this
Lease, in which case this Lease shall control. Landlord may, from time to time,
change such rules and regulations for the safety, care, or cleanliness of the
Building and related facilities, provided that such changes are applicable to
all tenants of the Building and will not unreasonably interfere with Tenant's
use of the Premises. Tenant shall be responsible for the compliance with such
rules and regulations by each Tenant Party.

     13.  Condemnation.
          ------------

          (a)  Total Taking. If the entire Building or Premises are taken by
               ------------
right of eminent domain or conveyed in lieu thereof (a "Taking"), this Lease
                                                        ------
shall terminate as of the date of the Taking.

                                      13
<PAGE>

          (b)  Partial Taking - Tenant's Rights. If any part of the Building
               --------------------------------
becomes subject to a Taking and such Taking will prevent Tenant from conducting
its business in the Premises in a manner reasonably comparable to that conducted
immediately before such Taking for a period of more than 180 days, then Tenant
may terminate this Lease as of the date of such Taking by giving written notice
to Landlord within 30 days after the Taking, and Rent shall be apportioned as of
the date of such Taking. If Tenant does not terminate this Lease, then Rent
shall be abated on a reasonable basis as to that portion of the Premises
rendered untenantable by the Taking.

          (c)  Partial Taking - Landlord's Rights. If any material portion, but
               ----------------------------------
less than all, of the Building becomes subject to a Taking, or if Landlord is
required to pay any of the proceeds received for a Taking to a Landlord's
Mortgagee, then Landlord may terminate this Lease by delivering written notice
thereof to Tenant within 30 days after such Taking, and Rent shall be
apportioned as of the date of such Taking. If Landlord does not so terminate
this Lease, then this Lease will continue, but if any portion of the Premises
has been taken, Rent shall abate as provided in the last sentence of Section
13.(b).

          (d)  Award. If any Taking occurs, then Landlord shall receive the
               -----
entire award or other compensation for the land on which the Building is
situated, the Building, and other improvements taken, and Tenant may separately
pursue a claim (to the extent it will not reduce Landlord's award) against the
condemnor for (i) the value of Tenant's personal property which Tenant is
entitled to remove under this Lease, moving costs, loss of business, (ii) an
award for Tenant's leasehold estate, and (iii) other claims it may have.

     14.  Fire or Other Casualty.
          ----------------------

          (a)  Repair Estimate. If the Premises or the Building are damaged
               ---------------
by fire or other casualty (a "Casualty"), Landlord shall, within 60 days after
                              --------
such Casualty, deliver to Tenant a good faith estimate (the "Damage Notice") of
                                                             -------------
the time needed to repair the damage caused by such Casualty.

          (b)  Landlord's and Tenant's Rights. If a material portion of the
               ------------------------------
Premises or the Building is damaged by Casualty such that Tenant is prevented
from conducting its business in the Premises in a manner reasonably comparable
to that conducted immediately before such Casualty and Landlord estimates that
the damage caused thereby cannot be repaired within 240 days after the Casualty,
then Tenant may terminate this Lease by delivering written notice to Landlord of
its election to terminate within 30 days after the Damage Notice has been
delivered to Tenant. If Tenant does not so timely terminate this Lease, then
(subject to Section 14.(c)) Landlord shall repair the Building or the Premises,
as the case may be, as provided below, and Rent for the portion of the Premises
rendered untenantable by the damage shall be abated on a reasonable basis from
the date of damage until the completion of the repair, unless a Tenant Party
caused such damage, in which case, Tenant shall continue to pay Rent without
abatement (except to the extent Landlord has obtained a policy of rental
reimbursement insurance, and actually receives the proceeds thereof).

          (c)  Landlord's Rights. If a Casualty damages a material portion of
               -----------------
the Building, and Landlord makes a good faith determination that restoring the
Premises would be uneconomical,

                                      14
<PAGE>

or if Landlord is required to pay any insurance proceeds arising out of the
Casualty to a Landlord's Mortgagee, then Landlord may terminate this Lease by
giving written notice of its election to terminate within 30 days after the
Damage Notice has been delivered to Tenant, and Basic Rent and Additional Rent
shall be abated as of the date of the Casualty.

          (d)  Repair Obligation. If neither party elects to terminate this
               -----------------
Lease following a Casualty, then Landlord shall, within a reasonable time after
such Casualty, begin to repair the Building and the Premises and shall proceed
with reasonable diligence to restore the Building and Premises to substantially
the same condition as they existed immediately before such Casualty; however,
Landlord shall not be required to repair or replace any of the furniture,
equipment, fixtures, and other improvements which may have been placed by, or at
the request of, Tenant or other occupants in the Building or the Premises, and
Landlord's obligation to repair or restore the Building or Premises shall be
limited to the extent of the insurance proceeds actually received by Landlord
for the Casualty in question.

     15.  Personal Property Taxes. Tenant shall be liable for all taxes levied
          -----------------------
or assessed against personal property, furniture, or fixtures placed by Tenant
in the Premises. If any taxes for which Tenant is liable are levied or assessed
against Landlord or Landlord's property and Landlord elects to pay the same, or
if the assessed value of Landlord's property is increased by inclusion of such
personal property, furniture or fixtures and Landlord elects to pay the taxes
based on such increase, then Landlord shall promptly give written notice of the
same to Tenant, and Tenant shall pay to Landlord, upon demand, the part of such
taxes for which Tenant is primarily liable hereunder; however, Landlord shall
not pay such amount if Tenant notifies Landlord that it will contest the
validity or amount of such taxes before Landlord makes such payment, and
thereafter diligently proceeds with such contest in accordance with law and if
the non-payment thereof does not pose a threat of loss or seizure of the
Building or interest of Landlord therein or impose any fee or penalty against
Landlord. Landlord shall promptly forward to Tenant any tax or assessment
notices that are received by Landlord and that Landlord can reasonably identify
as levying or taxing Tenant's property, furniture or fixtures; however, Landlord
shall not be liable for its failure to do so.

     16.  Events of Default. Each of the following occurrences shall be an
          -----------------
"Event of Default":
 ----------------

          (a)  Tenant's failure to pay Rent within five days after Landlord has
delivered notice to Tenant that the same is due; however, an Event of Default
shall occur hereunder without any obligation of Landlord to give any notice if
Landlord has given Tenant written notice under this Section 16.(a) on more than
one occasion during the twelve (12) month interval preceding such failure by
Tenant;

          (b)  Tenant fails to provide the Security Deposit required under
Section 5 and such failure shall continue for 5 days after written notice
thereof from Landlord to Tenant;

          (c)  Tenant's failure to perform, comply with, or observe any other
agreement or obligation of Tenant under this Lease and the continuance of such
failure for a period of more than 30 days after Landlord has delivered to Tenant
written notice thereof (provided, however, Tenant

                                      15
<PAGE>

shall have such additional time, not to exceed 90 days, to cure any such default
if Tenant has promptly commenced and is diligently pursuing such cure and
diligently prosecutes the same); and

          (d)  The filing of a petition by or against Tenant (the term "Tenant"
                                                                        ------
shall include, for the purpose of this Section 16.(d), any guarantor of Tenant's
obligations hereunder) (1) in any bankruptcy or other insolvency proceeding; (2)
seeking any relief under any state or federal debtor relief law; (3) for the
appointment of a liquidator or receiver for all or substantially all of Tenant's
property or for Tenant's interest in this Lease; or (4) for the reorganization
or modification of Tenant's capital structure; however, if such a petition is
filed against Tenant, then such filing shall not be an Event of Default unless
Tenant fails to have the proceedings initiated by such petition dismissed within
60 days after the filing thereof.

     17.  Remedies. Upon any Event of Default, Landlord may, in addition to
          --------
all other rights and remedies afforded Landlord hereunder or by law or equity,
take any of the following actions:

          (a)  Terminate this Lease by giving Tenant written notice thereof, in
which event Tenant shall pay to Landlord the sum of (1) all Rent accrued
hereunder through the date of termination, (2) all amounts due under Section
18.(a), and (3) an amount equal to (A) the total Rent that Tenant would have
been required to pay for the remainder of the Term discounted to present value
at a per annum rate equal to the "Prime Rate" as published on the date this
Lease is terminated by The Wall Street Journal, Southwest Edition, in its
listing of "Money Rates" minus one percent, minus (B) the then present fair
rental value of the Premises for such period, similarly discounted;

          (b)  Terminate Tenant's right to possess the Premises without
terminating this Lease by giving written notice thereof to Tenant, in which
event Tenant shall pay to Landlord (1) all Rent and other amounts accrued
hereunder to the date of termination of possession, (2) all amounts due from
time to time under Section 18.(a), and (3) all Rent and other net sums required
hereunder to be paid by Tenant during the remainder of the Term, diminished by
any net sums thereafter received by Landlord through reletting the Premises
during such period, after deducting all costs incurred by Landlord in reletting
the Premises. Landlord shall use reasonable efforts to relet the Premises on
such terms as Landlord in its sole discretion may determine (including a term
different from the Term, rental concessions, and alterations to, and improvement
of, the Premises); however, Landlord shall not be obligated to relet the
Premises before leasing other portions of the Building. Landlord shall not be
liable for, nor shall Tenant's obligations hereunder be diminished because of,
Landlord's failure to relet the Premises or to collect rent due for such
reletting. Tenant shall not be entitled to the excess of any consideration
obtained by reletting over the Rent due hereunder. Reentry by Landlord in the
Premises shall not affect Tenant's obligations hereunder for the unexpired Term;
rather, Landlord may, from time to time, bring an action against Tenant to
collect amounts due by Tenant, without the necessity of Landlord's waiting until
the expiration of the Term. Unless Landlord delivers written notice to Tenant
expressly stating that it has elected to terminate this Lease, all actions taken
by Landlord to dispossess or exclude Tenant from the Premises shall be deemed to
be taken under this Section 17.(b). If Landlord elects to proceed under this
Section 17.(b), it may at any time elect to terminate this Lease under Section
17.(a); or

                                      16
<PAGE>

          (c)  Additionally, without notice, Landlord may alter locks or other
security devices at the Premises to deprive Tenant of access thereto, and
Landlord shall not be required to provide a new key or right of access to
Tenant.

     18.  Payment by Tenant; Non-Waiver.
          -----------------------------

          (a)  Payment by Tenant. Upon any Event of Default, Tenant shall pay
               -----------------
to Landlord all costs incurred by Landlord (including court costs and reasonable
attorneys' fees and expenses) in (1 obtaining possession of the Premises, (2
removing and storing Tenant's or any other occupant's property, (3 repairing,
restoring, altering, remodeling, or otherwise putting the Premises into
condition acceptable to a new tenant, (4 if Tenant is dispossessed of the
Premises and this Lease is not terminated, reletting all or any part of the
Premises (including brokerage commissions, cost of tenant finish work, and other
costs incidental to such reletting), (5 performing Tenant's obligations which
Tenant failed to perform, and (6 enforcing, or advising Landlord of, its rights,
remedies, and recourses arising out of the Event of Default. To the full extent
permitted by law, Landlord and Tenant agree the federal and state courts of
Texas shall have exclusive jurisdiction over any matter relating to or arising
from this Lease and the parties' rights and obligations under this Lease.

          (b)  No Waiver. Landlord's acceptance of Rent following an Event of
               ---------
Default shall not waive Landlord's rights regarding such Event of Default. No
waiver by Landlord of any violation or breach of any of the terms contained
herein shall waive Landlord's rights regarding any future violation of such
term. Landlord's acceptance of any partial payment of Rent shall not waive
Landlord's rights with regard to the remaining portion of the Rent that is due,
regardless of any endorsement or other statement on any instrument delivered in
payment of Rent or any writing delivered in connection therewith; accordingly,
Landlord's acceptance of a partial payment of Rent shall not constitute an
accord and satisfaction of the full amount of the Rent that is due.

     19.  Surrender of Premises. No act by Landlord shall be deemed an
          ---------------------
acceptance of a surrender of the Premises, and no agreement to accept a
surrender of the Premises shall be valid unless it is in writing and signed by
Landlord. At the expiration or termination of this Lease, Tenant shall deliver
to Landlord the Premises with all improvements located therein in good repair
and condition, free of Hazardous Materials placed on the Premises during the
Term, broom-clean, reasonable wear and tear (and condemnation and Casualty
damage not caused by Tenant, as to which Sections 13 and 14 shall control)
excepted, and shall deliver to Landlord all keys to the Premises. Provided that
Tenant has performed all of its obligations hereunder, Tenant may remove all
unattached trade fixtures, furniture, and personal property placed in the
Premises by Tenant, and shall remove such alterations, additions, improvements,
trade fixtures, personal property, equipment, wiring, and furniture as Landlord
may request. Tenant shall repair all damage caused by such removal. All items
not so removed shall be deemed to have been abandoned by Tenant and may be
appropriated, sold, stored, destroyed, or otherwise disposed of by Landlord
without notice to Tenant and without any obligation to account for such items.
The provisions of this Section 19 shall survive the end of the Term.

                                      17
<PAGE>

     20.  Holding Over. If Tenant fails to vacate the Premises at the end of
          ------------
the Term, then Tenant shall be a tenant at will and, in addition to all other
damages and remedies to which Landlord may be entitled for such holding over,
Tenant shall pay, in addition to the other Rent, a daily Basic Rent equal to the
greater of (a) twice the daily Basic Rent payable during the last month of the
Term, or (b) 125% of the prevailing rental rate in the Building for similar
space. The provisions of this Section 20 shall not be deemed to limit or
constitute a waiver of any other rights or remedies of Landlord provided herein
or at law. If Tenant fails to surrender the Premises upon the termination or
expiration of this Lease, in addition to any other liabilities to Landlord
accruing therefrom, Tenant shall protect, defend, indemnify and hold Landlord
harmless from all loss, costs (including reasonable attorneys' fees) and
liability resulting from such failure, including, without limiting the
generality of the foregoing, any claims made by any succeeding tenant founded
upon such failure to surrender, and any lost profits to Landlord resulting
therefrom.

     21.  Certain Rights Reserved by Landlord. Provided that the exercise of
          -----------------------------------
such rights does not unreasonably interfere with Tenant's occupancy of the
Premises, Landlord (and its agents and contractors) shall have the following
rights:

          (a)  To decorate and to make inspections, repairs, alterations,
additions, changes, or improvements, whether structural or otherwise, in and
about the Building, or any part thereof; to enter upon the Premises and, during
the continuance of any such work, to temporarily close doors, entryways, public
space, and corridors in the Building; to interrupt or temporarily suspend
Building services and facilities; to change the name of the Building; and to
change the arrangement and location of entrances or passageways, doors, and
doorways, corridors, elevators, stairs, restrooms, or other public parts of the
Building;

          (b)  To take such reasonable measures as Landlord deems advisable for
the security of the Building and its occupants; evacuating the Building for
cause, suspected cause, or for drill purposes; temporarily denying access to the
Building; and closing the Building after normal business hours and on Sundays
and holidays, subject, however, to Tenant's right to enter when the Building is
closed after normal business hours under such reasonable regulations as Landlord
may prescribe from time to time; and

          (c)  To enter the Premises at reasonable hours to show the Premises to
prospective purchasers, lenders, or, during the last 18 months of the Term,
tenants.

          (d)  Any entry by the Landlord (or its agents and contractors) shall
be after reasonable prior notice to Tenant, except in the case of emergency. If
requested by Tenant, Landlord will use reasonable commercial efforts to enter
the Premises only after business hours; however, if Landlord's entry for any
purpose referenced above could have been done during normal business hours, but
Tenant requested Landlord's entry to be after normal business hours, then Tenant
agrees to reimburse Landlord for any additional costs incurred by Landlord as a
result thereof.

          (e)  Tenant may, by prior written notice, from time to time designate
up to 30,000 square feet of net rentable area of the Premises as secure areas,
as to which Tenant shall have the right to limit the people having access
thereto (absent emergencies) to only the persons necessary

                                      18
<PAGE>

to perform the repairs and maintenance contemplated by this Section 21. Except
in the case of emergency, Landlord shall have no access to the secured areas of
the Premises without being accompanied at all times by a designated
representative of Tenant.

     22.  Miscellaneous.
          -------------

          (a)  Landlord Transfer. Landlord may transfer any portion of the
               -----------------
Building and any of its rights under this Lease. If Landlord assigns its rights
under this Lease, then Landlord shall thereby be released from any further
obligations hereunder, provided that the assignee assumes Landlord's obligations
hereunder in writing.

          (b)  Landlord's Liability. The liability of Landlord to Tenant for
               --------------------
any default by Landlord under the terms of this Lease shall be limited to
Tenant's actual direct, but not consequential, damages therefor and shall be
recoverable only from the interest of Landlord in the Building, and Landlord
shall not be personally liable for any deficiency. This Section shall not limit
any remedies which Tenant may have for Landlord's defaults which do not involve
the personal liability of Landlord.

          (c)  Force Majeure. Other than for Tenant's obligations under this
               -------------
Lease that can be performed by the payment of money (e.g., payment of Rent and
maintenance of insurance), whenever a period of time is herein prescribed for
action to be taken by either party hereto, such party shall not be liable or
responsible for, and there shall be excluded from the computation of any such
period of time, any delays due to strikes, riots, acts of God, shortages of
labor or materials, war, governmental laws, regulations, or restrictions, or any
other causes of any kind whatsoever which are beyond the control of such party.

          (d)  Brokerage. Neither Landlord nor Tenant has dealt with any broker
               ---------
or agent in connection with the negotiation or execution of this Lease, other
than CB Richard Ellis, whose commission shall be paid by Landlord pursuant to a
separate agreement. Tenant and Landlord shall each indemnify the other against
all costs, expenses, attorneys' fees, and other liability for commissions or
other compensation claimed by any broker or agent claiming the same by, through,
or under the indemnifying party.

          (e)  Estoppel Certificates. From time to time, Tenant shall furnish
               ---------------------
to any party designated by Landlord, within ten business days after Landlord has
made a request therefor, a certificate signed by Tenant confirming and
containing such factual certifications and representations (if true) as to this
Lease as Landlord may reasonably request stating, (a) whether or not this Lease
is in full force and effect; (b) whether or not this Lease has been amended and
certifying as to copies of such amendments, if any; (c) whether or not there are
any existing defaults under this Lease to the knowledge of Tenant and specifying
the nature of such defaults, if any; (d) that Tenant will not amend, terminate
or make prepayment of more than one month's rent under this Lease or subordinate
this Lease to any lien subordinate to a mortgage; (e) that any notice required
hereunder to be given to Landlord shall be given also to such mortgagee or
assignee and any right of Tenant hereunder which is dependent on such notice
shall take effect only after notice so given; and (f) such other matters as may
reasonably be requested by Landlord, such mortgagee or assignee.

                                      19
<PAGE>

          (f)  Notices. All notices and other communications given pursuant to
               -------
this Lease shall be in writing and shall be (1 mailed by first class, United
States Mail, postage prepaid, certified, with return receipt requested, and
addressed to the parties hereto at the address specified next to their signature
block, (2 hand delivered to the intended address, or (3 sent by prepaid
telegram, cable, facsimile transmission, or telex followed by a confirmatory
letter. All notices shall be effective upon delivery to the address of the
addressee. The parties hereto may change their addresses by giving notice
thereof to the other in conformity with this provision.

          (g)  Separability. If any clause or provision of this Lease is
               ------------
illegal, invalid, or unenforceable under present or future laws, then the
remainder of this Lease shall not be affected thereby and in lieu of such clause
or provision, there shall be added as a part of this Lease a clause or provision
as similar in terms to such illegal, invalid, or unenforceable clause or
provision as may be possible and be legal, valid, and enforceable.

          (h)  Amendments; and Binding Effect. This Lease may not be amended
               ------------------------------
except by instrument in writing signed by Landlord and Tenant. No provision of
this Lease shall be deemed to have been waived by Landlord unless such waiver is
in writing signed by Landlord, and no custom or practice which may evolve
between the parties in the administration of the terms hereof shall waive or
diminish the right of Landlord to insist upon the performance by Tenant in
strict accordance with the terms hereof. The terms and conditions contained in
this Lease shall inure to the benefit of and be binding upon the parties hereto,
and upon their respective successors in interest and legal representatives,
except as otherwise herein expressly provided. This Lease is for the sole
benefit of Landlord and Tenant, and, other than Landlord's Mortgagee, no third
party shall be deemed a third party beneficiary hereof.

          (i)  Quiet Enjoyment. Provided Tenant has performed all of its
               ---------------
obligations hereunder, Tenant shall peaceably and quietly hold and enjoy the
Premises for the Term, without hindrance from Landlord or any party claiming by,
through, or under Landlord, but not otherwise, subject to the terms and
conditions of this Lease.

          (j)  No Merger. There shall be no merger of the leasehold estate
               ---------
hereby created with the fee estate in the Premises or any part thereof if the
same person acquires or holds, directly or indirectly, this Lease or any
interest in this Lease and the fee estate in the leasehold Premises or any
interest in such fee estate.

          (k)  No Offer. The submission of this Lease to Tenant shall not be
               --------
construed as an offer, and Tenant shall not have any rights under this Lease
unless Landlord executes a copy of this Lease and delivers it to Tenant.

          (l)  Entire Agreement. This Lease constitutes the entire agreement
               ----------------
between Landlord and Tenant regarding the subject matter hereof and supersedes
all oral statements and prior writings relating thereto, including that certain
letter agreement between Landlord and Tenant dated June 30, 1998. Except for
those set forth in this Lease, no representations, warranties, or agreements
have been made by Landlord or Tenant to the other with respect to this Lease or
the obligations of Landlord or Tenant in connection therewith. The normal rule
of construction that any ambiguities

                                      20
<PAGE>

be resolved against the drafting party shall not apply to the interpretation of
this Lease or any exhibits or amendments hereto.

          (m)  Governing Law. This Lease shall be governed by and construed in
               -------------
accordance with the laws of the State in which the Premises are located.

          (n)  Joint and Several Liability. If Tenant is comprised of more than
               ---------------------------
one party, each such party shall be jointly and severally liable for Tenant's
obligations under this Lease.

          (o)  Financial Reports. Tenant shall furnish to Landlord, promptly
               -----------------
upon its becoming available, each financial statement, report, notice or proxy
statement sent by Tenant to stockholders generally and each regular or periodic
report filed by Tenant with any securities exchange or the Securities and
Exchange Commission or any successor agency.

          (p)  Landlord's Fees. Whenever Tenant requests Landlord to take any
               ---------------
action or give any consent required or permitted under this Lease, Tenant will
reimburse Landlord for Landlord's reasonable, out-of-pocket costs incurred in
reviewing the proposed action or consent, including without limitation
reasonable attorneys', engineers' or architects' fees, within ten days after
Landlord's delivery to Tenant of a statement of such costs. Tenant will be
obligated to make such reimbursement without regard to whether Landlord consents
to any such proposed action.

          (q)  Telecommunications. Tenant and its telecommunications companies,
               ------------------
including but not limited to local exchange telecommunications companies and
alternative access vendor services companies shall have no right of access to
and within the Building, for the installation and operation of
telecommunications systems including but not limited to voice, video, data, and
any other telecommunications services provided over wire, fiber optic,
microwave, wireless, and any other transmission systems, for part or all of
Tenant's telecommunications within the Building and from the Building to any
other location without Landlord's prior written consent, which consent shall not
be withheld, conditioned or delayed: provided however, that Landlord may
withhold, condition or delay such consent if said telecommunications may
unreasonably interfere with other tenant's existing telecommunications uses,
require structural modifications, reduce the amount of leasable space in the
Building, interfere with any of the base Building systems or the operation of
the Building. If any of Tenant's telecommunications uses require access or use
of the rooftop of the Building, Landlord and Tenant shall negotiate a separate
license agreement relating to the same.

          (r)  General Definitions. The following terms shall have the
               -------------------
following meanings: "Laws" means all federal, state, and local laws, rules and
                     ----
regulations, all court orders, all governmental directives and governmental
orders, and all restrictive covenants affecting the Property, and "Law" means
                                                                   ---
any of the foregoing; "Affiliate" means (i) any Parent of Tenant or (ii) any
                       ---------
wholly owned subsidiary of Tenant, where "Parent" for the purpose of this
definition means any person directly or indirectly controlling Tenant, or any
direct or indirect (whether once or more removed) parent of Tenant's parent;
"Tenant Party" shall include Tenant, any assignees claiming by, through, or
 ------------
under Tenant, any subtenants claiming by, through, or under Tenant, and any
agents,

                                      21
<PAGE>

contractors, employees, invitees of the foregoing parties; and "including" means
including, without limitation.
---------

          (s)  Confidentiality. Tenant acknowledges that the economic terms and
               ---------------
conditions of this Lease are to remain confidential for Landlord's benefit, and
may not be disclosed by Tenant to anyone, by any manner or means, directly or
indirectly, without Landlord's prior written consent. The consent by Landlord to
any disclosures shall not be deemed to be a waiver on the part of Landlord of
any prohibition against any future disclosure. Unless otherwise mutually agreed,
no party shall make or authorize any press release of information regarding the
matters contemplated by, or any provisions or terms of, this Lease, except (i)
that a press release or press releases in mutually agreed upon form or forms
shall be issued by the parties following the execution of this Lease if
requested or required by either party, and (ii) after consultation with each
other, as required by law or stock exchange rule, or as necessary for the
assertion or enforcement of contractual rights.

          (t)  Hazardous Materials. The term "Hazardous Materials" means any
               -------------------            -------------------
substance, material, or waste which is now or hereafter classified or considered
to be hazardous, toxic, or dangerous under any Law relating to pollution or the
protection or regulation of human health, natural resources or the environment,
or poses or threatens to pose a hazard to the health or safety of persons on the
Premises or in the Building. Tenant shall not use, generate, store, or dispose
of, or permit the use, generation, storage or disposal of Hazardous Materials on
or about the Premises or the Building except in a manner and quantity necessary
for the ordinary performance of Tenant's business, and then in compliance with
all Laws. If Tenant breaches its obligations under this Section 22.(t), Landlord
may immediately take any and all action reasonably appropriate to remedy the
same, including taking all appropriate action to clean up or remediate any
contamination resulting from Tenant's use, generation, storage or disposal of
Hazardous Materials. Tenant shall defend, indemnify, and hold harmless Landlord
and its representatives and agents from and against any and all claims, demands,
liabilities, causes of action, suits, judgments, damages and expenses (including
reasonable attorneys' fees and cost of clean up and remediation) arising from
Tenant's failure to comply with the provisions of this Section 22.(t). This
indemnity provision shall survive termination or expiration of the Lease.

          (u)  List of Exhibits. All exhibits and attachments attached hereto
               -----------------
are incorporated herein by this reference.

          Exhibit A -  Outline of Premises
          Exhibit B -  Legal Description of Building
          Exhibit C -  Building Rules and Regulations
          Exhibit D -  Tenant Finish-Work Letter
          Exhibit E -  Parking
          Exhibit F -  Commencement Date Certificate
          Exhibit G -  Signage

     23.  Other Provisions.
          ----------------

                                      22
<PAGE>

LANDLORD AND TENANT EXPRESSLY DISCLAIM ANY IMPLIED WARRANTY THAT THE PREMISES
ARE SUITABLE FOR TENANT'S INTENDED COMMERCIAL PURPOSE, AND EXCEPT AS OTHERWISE
EXPRESSLY PROVIDED HEREIN TENANT'S OBLIGATION TO PAY RENT HEREUNDER IS NOT
DEPENDENT UPON THE CONDITION OF THE PREMISES OR THE PERFORMANCE BY LANDLORD OF
ITS OBLIGATIONS HEREUNDER, AND, EXCEPT AS OTHERWISE EXPRESSLY PROVIDED HEREIN,
TENANT SHALL CONTINUE TO PAY THE RENT, WITHOUT ABATEMENT, SETOFF OR DEDUCTION,
NOTWITHSTANDING ANY BREACH BY LANDLORD OF ITS DUTIES OR OBLIGATIONS HEREUNDER,
WHETHER EXPRESS OR IMPLIED.

     24.  Signage.
          -------

          (a)  Landlord hereby grants to Tenant the right to place and from time
to time replace signage in the interior of the Building of the size and type
described in Exhibit "G", which right shall be non-exclusive as to the street
             -----------
level lobby. Such signage shall be subject to the reasonable approval of
Landlord, but Landlord shall not object to the signage being or including
Tenant's name (or an abbreviation thereof) and/or Tenant's corporate logos in
the colors customarily utilized by Tenant.

          (b)  There shall be no additional cost to Tenant for the rights
granted in this Section 24; however all of Landlord's reasonable out of pocket
costs related to the construction and placement of Tenant's signage described in
(a) above shall be at Tenant's expense. Tenant may install the signage described
in Section 24 at any time after September 1, 1998. At the end of the Term,
Tenant shall remove all signage and restore the portion of the Building so
affected by the signage to the pre-existing condition.

     25.  Lender Approval. The parties acknowledge that (i) this Lease and
          ---------------
(ii) any amendment, modification or termination of this Lease is subject to the
consent of Principal Mutual Life Insurance Company ("Principal") and this Lease
                                                     ---------
is also subject to the execution of a Subordination, Non-Disturbance and
Attornment agreement in a form acceptable to Principal, Tenant and Landlord.

     Dated as of the date first above written.


TENANT:                   SYSCO CORPORATION


                          By:  /s/ John K. Stubblefield, Jr.
                             ---------------------------------------------------
                          Name: John K. Stubblefield, Jr.
                               -------------------------------------------------
                          Title: Senior Vice President & Chief Financial Officer
                                ------------------------------------------------
                          Address:  1390 Enclave Parkway
                                    Houston, Texas 77077
                                    Attention: General Counsel
                          Telecopy: 281/584-2510

                                      23
<PAGE>

LANDLORD:                         ENCLAVE PARKWAY REALTY, INC.


                                   By:   /s/ Thomas L. Langford
                                      -----------------------------------------
                                   Name: Thomas L. Langford
                                        ---------------------------------------
                                   Title: Executive Vice President
                                         --------------------------------------
                                   Address:  c/o Stone & Webster, Incorporated
                                             245 Summer Street
                                             Boston, Massachusetts 02210
                                             Attention: General Counsel
                                   Telecopy: 617/589-2201

                                      24
<PAGE>

                                   EXHIBIT A


                             [OUTLINE OF PREMISES]
                              -------------------

                                      A-1
<PAGE>

                                   EXHIBIT A
                                   ---------




                                 [FLOOR PLAN]




                                  Sixth Floor





                                 [FLOOR PLAN]




                                  Fifth Floor

                                      A-1
<PAGE>

                                   EXHIBIT B
                                   ---------

Reserve "I" in Block 6 of Partial Replat of Enclave, a subdivision in Harris
County, Texas, according to the map or plat thereof recorded in Volume 328, Page
13 of the Map Records of Harris County, Texas.

                                      B-1
<PAGE>

                                   EXHIBIT C
                                   ---------

                        BUILDING RULES AND REGULATIONS
                        ------------------------------

          The following rules and regulations shall apply to the Premises, the
Building, the parking garage associated therewith, and the appurtenances
thereto:

          1.   Sidewalks, doorways, vestibules, halls, stairways, and other
similar areas shall not be obstructed by tenants or used by any tenant for
purposes other than ingress and egress to and from their respective leased
premises and for going from one to another part of the Building.

          2.   Plumbing, fixtures and appliances shall be used only for the
purposes for which designed, and no sweepings, rubbish, rags or other unsuitable
material shall be thrown or deposited therein. Damage resulting to any such
fixtures or appliances from misuse by a tenant or its agents, employees or
invitees, shall be paid by such tenant.

          3.   No signs, advertisements or notices shall be painted or affixed
on or to any windows or doors or other part of the Building without the prior
written consent of Landlord. No nails, hooks or screws shall be driven or
inserted in any part of the Building except by Building maintenance personnel.
No curtains or other window treatments shall be placed between the glass and the
Building standard window treatments.

          4.   Landlord shall provide and maintain an alphabetical directory for
all tenants in the main lobby of the Building.

          5.   Landlord shall provide all door locks in each tenant's leased
premises, at the cost of such tenant, and no tenant shall place any additional
door locks in its leased premises without Landlord's prior written consent.
Landlord shall furnish to each tenant a reasonable number of keys to such
tenant's leased premises, at such tenant's cost, and no tenant shall make a
duplicate thereof.

          6.   Movement in or out of the Building of furniture or office
equipment, or dispatch or receipt by tenants of any bulky material, merchandise
or materials which require use of elevators or stairways, or movement through
the Building entrances or lobby shall be conducted under Landlord's supervision
at such times and in such a manner as Landlord may reasonably require. Each
tenant assumes all risks of and shall be liable for all damage to articles moved
and injury to persons or public engaged or not engaged in such movement,
including equipment, property and personnel of Landlord if damaged or injured as
a result of acts in connection with carrying out this service for such tenant.

          7.   Landlord may prescribe weight limitations and determine the
locations for safes and other heavy equipment or items, which shall in all cases
be placed in the Building so as to distribute weight in a manner acceptable to
Landlord which may include the use of such supporting devices as Landlord may
require. All damages to the Building caused by the installation or removal of
any

                                      C-1
<PAGE>

property of a tenant, or done by a tenant's property while in the Building,
shall be repaired at the expense of such tenant.

          8.   Corridor doors, when not in use, shall be kept closed. Nothing
shall be swept or thrown into the corridors, halls, elevator shafts or
stairways. No birds or animals shall be brought into or kept in, on or about any
tenant's leased premises. No portion of any tenant's leased premises shall at
any time be used or occupied as sleeping or lodging quarters.

          9.   Tenant shall cooperate with Landlord's employees in keeping its
leased premises neat and clean. Tenants shall not employ any person for the
purpose of such cleaning other than the Building's cleaning and maintenance
personnel.

          10.  To ensure orderly operation of the Building, no ice, mineral or
other water, towels, newspapers, etc. shall be delivered to any leased area
except by persons approved by Landlord.

          11.  Tenant shall not make or permit any vibration or improper,
objectionable or unpleasant noises or odors in the Building or otherwise
interfere in any way with other tenants or persons having business with them.

          12.  No machinery of any kind (other than normal office equipment)
shall be operated by any tenant on its leased area without Landlord's prior
written consent, nor shall any tenant use or keep in the Building any flammable
or explosive fluid or substance.

          13.  Landlord will not be responsible for lost or stolen personal
property, money or jewelry from tenant's leased premises or public or common
areas regardless of whether such loss occurs when the area is locked against
entry or not.

          14.  Tenant shall not conduct any activity on or about the Premises or
Building which will draw pickets, demonstrators, or the like.

          15.  All vehicles are to be currently licensed, parked for business
purposes having to do with Tenant's business operated in the Premises, parked
within designated parking spaces, one vehicle to each space. No vehicle shall be
parked as a "billboard" vehicle in the parking lot. Any vehicle parked
improperly may be towed away. Tenant, Tenant's agents, employees, vendors and
customers who do not operate or park their vehicles as required shall subject
the vehicle to being towed at the expense of the owner or driver. Landlord may
place a "boot" on the vehicle to immobilize it and may levy a charge of $50.00
to remove the "boot."

                                      C-2
<PAGE>

                                    EXHIBIT D
                                    ---------


                            TENANT FINISH-WORK LETTER
                            -------------------------

1.   Except as set forth in this Exhibit, Tenant accepts the Premises in their
     "AS-IS" condition on the date that this lease is entered into.
      -----

2.   On or before September 1, 1998, Tenant shall provide to Landlord for its
     approval final working drawings, prepared by an architect that has been
     approved by Landlord (which approval shall not unreasonably be withheld),
     of all improvements that Tenant proposes to install in the Premises; such
     working drawings shall include the partition layout, ceiling plan,
     electrical outlets and switches, telephone outlets, drawings for any
     modifications to the mechanical and plumbing systems of the Building, and
     detailed plans and specifications for the construction of the improvements
     called for under this Exhibit in accordance with all applicable
     governmental laws, codes, rules, and regulations. If any of Tenant's
     proposed construction work will affect the Building's HVAC, electrical,
     mechanical, or plumbing systems, then the working drawings pertaining
     thereto must be approved by the Building's engineer of record. Landlord's
     approval of such working drawings shall not be unreasonably withheld,
     provided that they comply with all laws, rules, and regulations, such
     working drawings are sufficiently detailed to allow construction of the
     improvements in a good and workmanlike manner, and the improvements
     depicted thereon conform to the rules and regulations promulgated from time
     to time by Landlord for the construction of tenant improvements (a copy of
     which has been delivered to Tenant). As used herein, "Working Drawings"
                                                           ----------------
     shall mean the final working drawings approved by Landlord, as amended from
     time to time by any approved changes thereto, and "Work" shall mean all
                                                        ----
     improvements to be constructed in accordance with and as indicated on the
     Working Drawings. Landlord's approval of the Working Drawings shall not be
     a representation or warranty of Landlord that such drawings are adequate
     for any use or comply with any law, but shall merely be the consent of
     Landlord thereto. Tenant shall, at Landlord's request, sign the Working
     Drawings to evidence its review and approval thereof. All changes in the
     Work must receive the prior written approval of Landlord, and in the event
     of any such approved change Tenant shall, upon completion of the Work,
     furnish Landlord with an accurate, reproducible "as-built" plan of the
     improvements as constructed.

3.   The Work shall be performed only by contractors and subcontractors approved
     in writing by Landlord, which approval shall not be unreasonably withheld.
     All contractors and subcontractors shall be required to procure and
     maintain insurance against such risks, in such amounts, and with such
     companies as Landlord may reasonably require. Certificates of such
     insurance, with paid receipts therefor, must be received by Landlord before
     the Work is commenced. The Work shall be performed in a good and
     workmanlike manner free of defects, shall conform strictly with the Working
     Drawings, and shall be performed in such a manner and at such times as and
     not to interfere with or delay Landlord's other contractors, the operation
     of the Building, and the occupancy thereof by other tenants. All
     contractors

                                      D-1
<PAGE>

     and subcontractors shall contact Landlord and schedule time periods during
     which they may use Building facilities in connection with the Work (e.g.,
     elevators, excess electricity, etc.).

4.   If a delay in the performance of the Work occurs because of any change by
     Tenant to the Working Drawings, or if Tenant or Tenant's agents otherwise
     delays completion of the Work, then, notwithstanding any provision to the
     contrary in this Lease, Tenant's obligation to pay Rent hereunder shall
     commence on the scheduled Commencement Date.

5.   Tenant shall, from and after the date of delivery to Tenant of each portion
     of the Premises, construct all of the initial leasehold improvements with
     respect such portion of the Premises required for Tenant's occupancy of the
     Premises. Tenant shall pay for all costs and expenses relating thereto,
     including the costs of labor, materials and the preparation of all plans
     and specifications. In connection therewith, Landlord will pay to Tenant
     the Construction Allowance in the amount set forth below. Landlord shall
     pay the Construction Allowance within fifteen (15) days after the
     Landlord's receipt of final lien waivers from Tenant's Contractor (as
     defined below) and each subcontractor thereof performing work in accordance
     with this Exhibit D. Tenant shall supply partial lien releases from general
     and subcontractors from time to time to the extent that the same are
     provided to Tenant. "Tenant Contractor" shall mean such construction firm
                          -----------------
     as may be reasonably approved by Landlord, as designated by Tenant in
     writing to Landlord.

6.   The entire cost of performing the Work (including, without limitation,
     design of the Work and preparation of the Working Drawings, costs of
     construction labor and materials, electrical usage during construction,
     additional janitorial services, general tenant signage, related taxes and
     insurance costs, all of which costs are herein collectively called the
     "Total Construction Costs") in excess of the Construction Allowance
      ------------------------
     (hereinafter defined) shall be paid by Tenant.

7.   Landlord shall provide to Tenant a construction allowance (the
     "Construction Allowance") equal to the lesser of $6.00 per usable square
      -----------------------
     foot in the Premises or the Total Construction Costs, as adjusted for any
     approved changes to the Work; however, if Tenant or its agent is managing
     the performance of the Work, then Tenant shall not become entitled to full
     credit for the Construction Allowance until the Work has been substantially
     completed and Tenant has caused to be delivered to Landlord all invoices
     from contractors, subcontractors, and suppliers evidencing the cost of
     performing the Work, together with lien waivers from such parties, and a
     consent of the surety to the finished Work (if applicable) and a
     certificate of occupancy from the appropriate governmental authority, if
     applicable to the Work, or evidence of governmental inspection and approval
     of the Work. The Construction Allowance may only be applied against
     invoices that are incurred prior to the Commencement Date or during the
     first 24 months of the Term, and may not be applied against expenses for
     items other than Tenant improvements.

8.   (a)  As otherwise provided below, Tenant shall cause Tenant's Contractor to
          construct all of the initial leasehold improvements in a good and
          workmanlike manner, in accordance with the Working Drawings and all
          applicable legal requirements. Tenant

                                      D-2
<PAGE>

          shall include, for the express benefit of it, Landlord, and Landlord's
          Mortgagee the following provisions in the contract between Tenant and
          Tenant's Contractor:

               (i)    Tenant's Contractor and its subcontractors shall at all
                      times comply with Landlord's construction rules and
                      regulations.

               (ii)   All warranties set forth in the contract between Tenant's
                      Contractor and Tenant shall run in favor of Landlord and
                      Landlord's Mortgagee.

               (iii)  Tenant's Contractor shall defend, indemnify and hold
                      Landlord, and its employees, agents, and contractors and
                      lenders harmless against any claim for personal injury or
                      property damage arising out of the construction of the
                      initial leasehold improvements, provided that, at the
                      request of Landlord or Tenant's Contractor, such parties
                      shall enter into an agreement providing for waiver of
                      claims and subrogation against damage to property of each
                      other on the same basis as between Landlord and Tenant
                      under the Lease.

     (b)  Landlord shall not be liable in any way for any injury, loss or damage
          which may occur to any of Tenant's installations during construction
          of the initial leasehold improvements, the same being solely at
          Tenant's risk. While in or upon the Premises and the Building for the
          purposes of performing work hereunder, Tenant and Tenant's Contractor
          shall comply with all terms and provisions of the Lease, which shall
          govern the relationship of the parties except as expressly provided
          otherwise herein.

9.   Landlord or its affiliate or agent shall be entitled to review and
     supervise the Work to ensure that Landlord's rights are protected. Tenant
     shall supervise the Work, and act as a liaison between the Contractor and
     Landlord and coordinate the relationship between the Work, the Building,
     and the Building's systems.

10.  Tenant shall, at its expense, obtain (and furnish a copy to Landlord) all
     permits and approvals from all appropriate governmental authorities prior
     to commencing construction of the portion of the initial leasehold
     improvements then to be constructed by Tenant's Contractor. Tenant shall
     also obtain prior to occupancy, a certificate of occupancy permitting
     occupancy and use of the Premises for the uses permitted under the Lease.
     Tenant's failure to do so shall not cause a delay of the Commencement Date.
     Landlord shall reasonably cooperate with Tenant, at no cost to Landlord, in
     connection with Tenant's efforts to obtain all such necessary approvals and
     permits and the certificate of occupancy for the Premises.

                                      D-3
<PAGE>

                                    EXHIBIT E
                                    ---------


                                     PARKING
                                     -------


     Tenant may use five (5) undesignated non-reserved parking spaces per 1,000
rentable square feet in the Premises for parking for Tenants', contractors,
agents and employees (but only if the same are occupants or visitors of the
Building) in the adjacent parking garage associated with the Building (the
"Parking Area") during the Term at such rates and subject to such terms,
 ------------
conditions and regulations as are from time to time charged or applicable to
patrons of the Parking Area. Provided that there is not Event of Default under
the Lease, Tenant's obligation to pay the parking charges for such spaces shall
be abated for the ten year initial period of the Term. If Tenant sublets any
portion of the Premises or assigns any of its interest in this Lease, then the
parking spaces allocated to Tenant hereunder shall be reduced to the extent the
ratio between the rentable square feet of the Premises and the parking spaces
granted to Tenant hereunder exceeds the Building standard ratio of parking space
per rentable square foot as established by Landlord from time to time.

                                      E-1
<PAGE>

                                    EXHIBIT F
                                    ---------


                          COMMENCEMENT DATE CERTIFICATE
                          -----------------------------

         THIS COMMENCEMENT DATE CERTIFICATE is executed in connection with the
Lease Agreement dated July ____, 1998 between ENCLAVE PARKWAY REALTY, INC., a
Delaware corporation, as Landlord, and SYSCO CORPORATION, a Delaware
corporation, as Tenant.

         Landlord and Tenant hereby agree that:

         1.    The Floor delivery date for each floor of the Premises is as
               follows:

                   Floor                         Floor Commencement Date
                   -----                         -----------------------


         2.    The Lease Commencement Date is ______________________.

         All other terms and conditions of the Lease are hereby ratified and
acknowledged to be unchanged.

         IN WITNESS WHEREOF, this Commencement Date Certificate is executed this
________day of ____________________, 1998.

"LANDLORD"                                  "TENANT"

ENCLAVE PARKWAY REALTY, INC.                SYSCO CORPORATION


By:______________________________           By:______________________________
Name:____________________________           Name:____________________________
Title:___________________________           Title:___________________________

                                      F-1
<PAGE>

                                  Exhibit "G"








         [LOGO OF SYSCO]



         Signage of the above to be of such materials, size and with such
         lighting as mutually agreed by the parties to the Lease.