<PAGE>

                                                                     EXHIBIT 4.6

         FORM OF INDENTURE TO BE ENTERED INTO BETWEEN THE COMPANY AND A
                               TRUSTEE TO BE NAMED

================================================================================

                                  NUVELO, INC.

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

                                    INDENTURE

                           Dated as of _________, 200_

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

                                [Name of Trustee]

                                     Trustee

================================================================================

<PAGE>

                                TABLE OF CONTENTS
<TABLE>
<CAPTION>
                                                                                                                Page
                                                                                                                ----
<S>                                                                                                             <C>
ARTICLE I. DEFINITIONS AND INCORPORATION BY REFERENCE.........................................................    2
         Section 1.1.      Definitions........................................................................    2
         Section 1.2.      Other Definitions..................................................................    6
         Section 1.3.      Incorporation by Reference of Trust Indenture Act..................................    6
         Section 1.4.      Rules of Construction..............................................................    7
ARTICLE II. THE SECURITIES....................................................................................    7
         Section 2.1.      Issuable in Series.................................................................    7
         Section 2.2.      Establishment of Terms of Series of Securities.....................................    7
         Section 2.3.      Execution and Authentication.......................................................   10
         Section 2.4.      Registrar and Paying Agent.........................................................   11
         Section 2.5.      Paying Agent to Hold Money in Trust................................................   11
         Section 2.6.      Securityholder Lists...............................................................   12
         Section 2.7.      Transfer and Exchange..............................................................   12
         Section 2.8.      Mutilated, Destroyed, Lost and Stolen Securities...................................   12
         Section 2.9.      Outstanding Securities.............................................................   13
         Section 2.10.     Treasury Securities................................................................   14
         Section 2.11.     Temporary Securities...............................................................   14
         Section 2.12.     Cancellation.......................................................................   14
         Section 2.13.     Defaulted Interest.................................................................   14
         Section 2.14.     Global Securities..................................................................   14
         Section 2.15.     CUSIP Numbers......................................................................   16
ARTICLE III. REDEMPTION.......................................................................................   16
         Section 3.1.      Notice to Trustee..................................................................   16
         Section 3.2.      Selection of Securities to be Redeemed.............................................   16
         Section 3.3.      Notice of Redemption...............................................................   16
         Section 3.4.      Effect of Notice of Redemption.....................................................   17
         Section 3.5.      Deposit of Redemption Price........................................................   17
         Section 3.6.      Securities Redeemed in Part........................................................   17
ARTICLE IV. COVENANTS.........................................................................................   18
         Section 4.1.      Payment of Principal and Interest..................................................   18
         Section 4.2.      SEC Reports........................................................................   18
         Section 4.3.      Compliance Certificate.............................................................   18
         Section 4.4.      Stay, Extension and Usury Laws.....................................................   18
         Section 4.5.      Corporate Existence................................................................   19
         Section 4.6.      Taxes..............................................................................   19
ARTICLE V. SUCCESSORS.........................................................................................   19
         Section 5.1.      When Company May Merge, Etc........................................................   19
         Section 5.2.      Successor Corporation Substituted..................................................   19
ARTICLE VI. DEFAULTS AND REMEDIES.............................................................................   20
         Section 6.1.      Events of Default..................................................................   20
         Section 6.2.      Acceleration of Maturity; Rescission and Annulment.................................   21
         Section 6.3.      Collection of Indebtedness and Suits for Enforcement by Trustee....................   22
         Section 6.4.      Trustee May File Proofs of Claim...................................................   23
</TABLE>

                                       i

<PAGE>

<TABLE>
<S>                                                                                                              <C>
         Section 6.5.      Trustee May Enforce Claims Without Possession of Securities........................   23
         Section 6.6.      Application of Money Collected.....................................................   24
         Section 6.7.      Limitation on Suits................................................................   24
         Section 6.8.      Unconditional Right of Holders to Receive Principal and Interest...................   25
         Section 6.9.      Restoration of Rights and Remedies.................................................   25
         Section 6.10.     Rights and Remedies Cumulative.....................................................   25
         Section 6.11.     Delay or Omission Not Waiver.......................................................   25
         Section 6.12.     Control by Holders.................................................................   25
         Section 6.13.     Waiver of Past Defaults............................................................   26
         Section 6.14.     Undertaking for Costs..............................................................   26
ARTICLE VII. TRUSTEE..........................................................................................   26
         Section 7.1.      Duties of Trustee..................................................................   26
         Section 7.2.      Rights of Trustee..................................................................   28
         Section 7.3.      Individual Rights of Trustee.......................................................   28
         Section 7.4.      Trustee's Disclaimer...............................................................   28
         Section 7.5.      Notice of Defaults.................................................................   29
         Section 7.6.      Reports by Trustee to Holders......................................................   29
         Section 7.7.      Compensation and Indemnity.........................................................   29
         Section 7.8.      Replacement of Trustee.............................................................   30
         Section 7.9.      Successor Trustee by Merger, etc...................................................   31
         Section 7.10.     Eligibility; Disqualification......................................................   31
         Section 7.11.     Preferential Collection of Claims Against Company..................................   31
ARTICLE VIII. SATISFACTION AND DISCHARGE; DEFEASANCE..........................................................   31
         Section 8.1.      Satisfaction and Discharge of Indenture............................................   31
         Section 8.2.      Application of Trust Funds; Indemnification........................................   32
         Section 8.3.      Legal Defeasance of Securities of any Series.......................................   33
         Section 8.4.      Covenant Defeasance................................................................   35
         Section 8.5.      Repayment to Company...............................................................   36
         Section 8.6.      Reinstatement......................................................................   36
ARTICLE IX. AMENDMENTS AND WAIVERS............................................................................   36
         Section 9.1.      Without Consent of Holders.........................................................   36
         Section 9.2.      With Consent of Holders............................................................   37
         Section 9.3.      Limitations........................................................................   37
         Section 9.4.      Compliance with Trust Indenture Act................................................   38
         Section 9.5.      Revocation and Effect of Consents..................................................   38
         Section 9.6.      Notation on or Exchange of Securities..............................................   38
         Section 9.7.      Trustee Protected..................................................................   39
ARTICLE X. MISCELLANEOUS......................................................................................   39
         Section 10.1.     Trust Indenture Act Controls.......................................................   39
         Section 10.2.     Notices............................................................................   39
         Section 10.3.     Communication by Holders with Other Holders........................................   40
         Section 10.4.     Certificate and Opinion as to Conditions Precedent.................................   40
         Section 10.5.     Statements Required in Certificate or Opinion......................................   40
         Section 10.6.     Rules by Trustee and Agents........................................................   40
         Section 10.7.     Legal Holidays.....................................................................   41
         Section 10.8.     No Recourse Against Others.........................................................   41
</TABLE>

                                       ii

<PAGE>

<TABLE>
<S>                                                                                                              <C>
         Section 10.9.     Counterparts.......................................................................   41
         Section 10.10.    Governing Laws.....................................................................   41
         Section 10.11.    No Adverse Interpretation of Other Agreements......................................   41
         Section 10.12.    Successors.........................................................................   41
         Section 10.13.    Severability.......................................................................   42
         Section 10.14.    Table of Contents, Headings, Etc...................................................   42
         Section 10.15.    Securities in a Foreign Currency or in ECU.........................................   42
         Section 10.16.    Judgment Currency..................................................................   43
ARTICLE XI. SINKING FUNDS.....................................................................................   43
         Section 11.1.     Applicability of Article...........................................................   43
         Section 11.2.     Satisfaction of Sinking Fund Payments with Securities..............................   43
         Section 11.3.     Redemption of Securities for Sinking Fund..........................................   44
</TABLE>

                                      iii

<PAGE>

                                  NUVELO, INC.

         Reconciliation and tie between Trust Indenture Act of 1939 and
                     Indenture, dated as of _________, 200_

<TABLE>
<S>                                                                          <C>
 Section 310(a)(1)  ...................................................      7.10
            (a)(2)  ...................................................      7.10
            (a)(3)  ...................................................      Not Applicable
            (a)(4)  ...................................................      Not Applicable
            (a)(5)  ...................................................      7.10
               (b)  ...................................................      7.10
    Section 311(a)  ...................................................      7.11
               (b)  ...................................................      7.11
               (c)  ...................................................      Not Applicable
    Section 312(a)  ...................................................      2.6
               (b)  ...................................................      10.3
               (c)  ...................................................      10.3
    Section 313(a)  ...................................................      7.6
            (b)(1)  ...................................................      7.6
            (b)(2)  ...................................................      7.6
            (c)(1)  ...................................................      7.6
               (d)  ...................................................      7.6
    Section 314(a)  ...................................................      4.2, 10.5
               (b)  ...................................................      Not Applicable
            (c)(1)  ...................................................      10.4
            (c)(2)  ...................................................      10.4
            (c)(3)  ...................................................      Not Applicable
               (d)  ...................................................      Not Applicable
               (e)  ...................................................      10.5
               (f)  ...................................................      Not Applicable
    Section 315(a)  ...................................................      7.1
               (b)  ...................................................      7.5
               (c)  ...................................................      7.1
               (d)  ...................................................      7.1
               (e)  ...................................................      6.14
    Section 316(a)  ...................................................      2.10
         (a)(1)(A)  ...................................................      6.12
         (a)(1)(B)  ...................................................      6.13
               (b)  ...................................................      6.8
 Section 317(a)(1)  ...................................................      6.3
            (a)(2)  ...................................................      6.4
               (b)  ...................................................      2.5
    Section 318(a)  ...................................................      10.1
</TABLE>

------------------------
Note: This reconciliation and tie shall not, for any purpose, be deemed to be
part of the Indenture.

<PAGE>

                  Indenture dated as of ___________, 200_ between Nuvelo, Inc.,
a Nevada corporation ("Company"), and [Name of Trustee], a ________________
("Trustee").

                  Each party agrees as follows for the benefit of the other
party and for the equal and ratable benefit of the Holders of the Securities
issued under this Indenture.

                                   ARTICLE I.
                   DEFINITIONS AND INCORPORATION BY REFERENCE

         Section 1.1.      Definitions.

                  "Additional Amounts" means any additional amounts which are
required hereby or by any Security, under circumstances specified herein or
therein, to be paid by the Company in respect of certain taxes imposed on
Holders specified therein and which are owing to such Holders.

                  "Affiliate" of any specified person means any other person
directly or indirectly controlling or controlled by or under direct or indirect
common control with such specified person. For the purposes of this definition,
"control" (including, with correlative meanings, the terms "controlled by" and
"under common control with"), as used with respect to any person, shall mean the
possession, directly or indirectly, of the power to direct or cause the
direction of the management or policies of such person, whether through the
ownership of voting securities or by agreement or otherwise.

                  "Agent" means any Registrar, Paying Agent, Service Agent or
authenticating agent.

                  "Authorized Newspaper" means a newspaper in an official
language of the country of publication customarily published at least once a day
for at least five days in each calendar week and of general circulation in the
place in connection with which the term is used. If it shall be impractical to
make any publication of any notice required hereby in an Authorized Newspaper,
any publication or other notice in lieu thereof that is made or given by the
Trustee shall constitute a sufficient publication of such notice.

                  "Bearer" means anyone in possession from time to time of a
Bearer Security.

                  "Bearer Security" means any Security, including any interest
coupon appertaining thereto, that does not provide for the identification of the
Holder thereof.

                  "Board of Directors" means the Board of Directors of the
Company or any duly authorized committee thereof.

                  "Board Resolution" means a copy of a resolution certified by
the Secretary or an Assistant Secretary of the Company to have been adopted by
the Board of Directors or pursuant to authorization by the Board of Directors
and to be in full force and effect on the date of the certificate and delivered
to the Trustee.

                                       2

<PAGE>

                  "Business Day" means, unless otherwise provided by Board
Resolution, Officers' Certificate or supplemental indenture hereto for a
particular Series, any day except a Saturday, Sunday or a legal holiday in The
City of New York or the City of San Francisco on which banking institutions are
authorized or required by law, regulation or executive order to close.

                  "Company" means the party named as such above until a
successor replaces it and thereafter means the successor.

                  "Company Order" means a written order signed in the name of
the Company by two Officers, one of whom must be the Company's chief executive
officer, chief financial officer or principal accounting officer.

                  "Company Request" means a written request signed in the name
of the Company by its Chairman of the Board, a President or a Vice President,
and by its Treasurer, an Assistant Treasurer, its Secretary or an Assistant
Secretary, and delivered to the Trustee.

                  "Corporate Trust Office" means the office of the Trustee at
which at any particular time its corporate trust business shall be principally
administered.

                  "Debt" of any person as of any date means, without
duplication, all indebtedness of such person in respect of borrowed money,
including all interest, fees and expenses owed in respect thereto (whether or
not the recourse of the lender is to the whole of the assets of such person or
only to a portion thereof), or evidenced by bonds, notes, debentures or similar
instruments.

                  "Default" means any event which is, or after notice or passage
of time would be, an Event of Default.

                  "Depository" means, with respect to the Securities of any
Series issuable or issued in whole or in part in the form of one or more Global
Securities, the person designated as Depository for such Series by the Company,
which Depository shall be a clearing agency registered under the Exchange Act;
and if at any time there is more than one such person, "Depository" as used with
respect to the Securities of any Series shall mean the Depository with respect
to the Securities of such Series.

                  "Discount Security" means any Security that provides for an
amount less than the stated principal amount thereof to be due and payable upon
declaration of acceleration of the maturity thereof pursuant to Section 6.2.

                  "Dollars" means the currency of The United States of America.

                  "ECU" means the European Currency Unit as determined by the
Commission of the European Union.

                  "Exchange Act" means the Securities Exchange Act of 1934, as
amended.

                  "Foreign Currency" means any currency or currency unit issued
by a government other than the government of The United States of America.

                                       3

<PAGE>

                  "Foreign Government Obligations" means with respect to
Securities of any Series that are denominated in a Foreign Currency, (i) direct
obligations of the government that issued or caused to be issued such currency
for the payment of which obligations its full faith and credit is pledged or
(ii) obligations of a person controlled or supervised by or acting as an agency
or instrumentality of such government the timely payment of which is
unconditionally guaranteed as a full faith and credit obligation by such
government, which, in either case under clauses (i) or (ii), are not callable or
redeemable at the option of the issuer thereof.

                  "Global Security" or "Global Securities" means a Security or
Securities, as the case may be, in the form established pursuant to Section 2.2
evidencing all or part of a Series of Securities, issued to the Depository for
such Series or its nominee, and registered in the name of such Depository or
nominee.

                  "Holder" or "Securityholder" means a person in whose name a
Security is registered or the holder of a Bearer Security.

                  "Indenture" means this Indenture as amended from time to time
and shall include the form and terms of particular Series of Securities
established as contemplated hereunder.

                  "interest" with respect to any Discount Security which by its
terms bears interest only after Maturity, means interest payable after Maturity.

                  "Maturity," when used with respect to any Security or
installment of principal thereof, means the date on which the principal of such
Security or such installment of principal becomes due and payable as therein or
herein provided, whether at the Stated Maturity or by declaration of
acceleration, call for redemption, notice of option to elect repayment or
otherwise.

                  "Officer" means the Chairman of the Board, any President, any
Vice-President, the Treasurer, the Secretary, any Assistant Treasurer or any
Assistant Secretary of the Company.

                  "Officers' Certificate" means a certificate signed by two
Officers, one of whom must be the Company's principal executive officer,
principal financial officer or principal accounting officer.

                  "Opinion of Counsel" means a written opinion of legal counsel
who is acceptable to the Trustee. The counsel may be an employee of or counsel
to the Company.

                  "person" means any individual, corporation, partnership, joint
venture, association, limited liability company, joint-stock company, trust,
unincorporated organization or government or any agency or political subdivision
thereof.

                  "principal" of a Security means the principal of the Security
plus, when appropriate, the premium, if any, on, and any Additional Amounts in
respect of, the Security.

                  "Responsible Officer" means any officer of the Trustee in its
Corporate Trust Office and also means, with respect to a particular corporate
trust matter, any other officer to whom any corporate trust matter is referred
because of his or her knowledge of and familiarity with a particular subject.

                                       4

<PAGE>

                  "SEC" means the Securities and Exchange Commission.

                  "Securities" means the debentures, notes or other debt
instruments of the Company of any Series authenticated and delivered under this
Indenture.

                  "Series" or "Series of Securities" means each series of
debentures, notes or other debt instruments of the Company created pursuant to
Sections 2.1 and 2.2 hereof.

                  "Significant Subsidiary" means (i) any direct or indirect
Subsidiary of the Company that would be a "significant subsidiary" as defined in
Article 1, Rule 1-02 of Regulation S-X, promulgated pursuant to the Securities
Act of 1933, as amended, as such regulation is in effect on the date hereof, or
(ii) any group of direct or indirect Subsidiaries of the Company that, taken
together as a group, would be a "significant subsidiary" as defined in Article
1, Rule 1-02 of Regulation S-X, promulgated pursuant to the Securities Act of
1933, as amended, as such regulation is in effect on the date hereof.

                  "Stated Maturity" when used with respect to any Security or
any installment of principal thereof or interest thereon, means the date
specified in such Security as the fixed date on which the principal of such
Security or such installment of principal or interest is due and payable.

                  "Subsidiary" of any specified person means any corporation of
which at least a majority of the outstanding stock having by the terms thereof
ordinary voting power for the election of directors of such corporation
(irrespective of whether or not at the time stock of any other class or classes
of such corporation shall have or might have voting power by reason of the
happening of any contingency) is at the time directly or indirectly owned by
such person, or by one or more other Subsidiaries, or by such person and one or
more other Subsidiaries.

                  "TIA" means the Trust Indenture Act of 1939 (15 U.S. Code
Sections 77aaa-77bbbb) as in effect on the date of this Indenture; provided,
however, that in the event the Trust Indenture Act of 1939 is amended after such
date, "TIA" means, to the extent required by any such amendment, the Trust
Indenture Act as so amended.

                  "Trustee" means the person named as the "Trustee" in the first
paragraph of this instrument until a successor Trustee shall have become such
pursuant to the applicable provisions of this Indenture, and thereafter
"Trustee" shall mean or include each person who is then a Trustee hereunder, and
if at any time there is more than one such person, "Trustee" as used with
respect to the Securities of any Series shall mean the Trustee with respect to
Securities of that Series.

                  "U.S. Government Obligations" means securities which are (i)
direct obligations of The United States of America for the payment of which its
full faith and credit is pledged or (ii) obligations of a person controlled or
supervised by and acting as an agency or instrumentality of The United States of
America the payment of which is unconditionally guaranteed as a full faith and
credit obligation by The United States of America, and which in the case of (i)
and (ii) are not callable or redeemable at the option of the issuer thereof, and
shall also include a depository receipt issued by a bank or trust company as
custodian with respect to any such U.S. Government Obligation or a specific
payment of interest on or principal of any such U.S.

                                       5

<PAGE>

Government Obligation held by such custodian for the account of the holder of a
depository receipt, provided that (except as required by law) such custodian is
not authorized to make any deduction from the amount payable to the holder of
such depository receipt from any amount received by the custodian in respect of
the U.S. Government Obligation evidenced by such depository receipt.

         Section 1.2.      Other Definitions.

<TABLE>
<CAPTION>
                                                         DEFINED IN
    TERM                                                   SECTION
    ----                                                   -------
<S>                                                      <C>
"Bankruptcy Law"                                              6.1
"Custodian"                                                   6.1
"Event of Default"                                            6.1
"Journal"                                                   10.15
"Judgment Currency"                                         10.16
"Legal Holiday"                                              10.7
"mandatory sinking fund payment"                             11.1
"Market Exchange Rate"                                      10.15
"New York Banking Day"                                      10.16
"optional sinking fund payment"                              11.1
"Paying Agent"                                                2.4
"Registrar"                                                   2.4
"Required Currency"                                         10.16
"Service Agent"                                               2.4
"successor person"                                            5.1
</TABLE>

         Section 1.3.      Incorporation by Reference of Trust Indenture Act.

                  Whenever this Indenture refers to a provision of the TIA, the
provision is incorporated by reference in and made a part of this Indenture. The
following TIA terms used in this Indenture have the following meanings:

                  "Commission" means the SEC.

                  "indenture securities" means the Securities.

                  "indenture security holder" means a Securityholder.

                  "indenture to be qualified" means this Indenture.

                  "indenture trustee" or "institutional trustee" means the
                  Trustee.

                  "obligor" on the indenture securities means the Company and
                  any successor obligor upon the Securities.

                                       6

<PAGE>

                  All other terms used in this Indenture that are defined by the
TIA, defined by TIA reference to another statute or defined by SEC rule under
the TIA and not otherwise defined herein are used herein as so defined.

         Section 1.4.      Rules of Construction.

                  Unless the context otherwise requires:

                  (a)      a term has the meaning assigned to it;

                  (b)      an accounting term not otherwise defined has the
         meaning assigned to it in accordance with generally accepted accounting
         principles;

                  (c)      references to "generally accepted accounting
         principles" shall mean generally accepted accounting principles in
         effect as of the time when and for the period as to which such
         accounting principles are to be applied;

                  (d)      "or" is not exclusive;

                  (e)      words in the singular include the plural, and in the
         plural include the singular; and

                  (f)      provisions apply to successive events and
         transactions.

                                  ARTICLE II.
                                 THE SECURITIES

         Section 2.1.      Issuable in Series.

                  The aggregate principal amount of Securities that may be
authenticated and delivered under this Indenture is unlimited. The Securities
may be issued in one or more Series. All Securities of a Series shall be
identical except as may be set forth in a Board Resolution, a supplemental
indenture or an Officers' Certificate detailing the adoption of the terms
thereof pursuant to the authority granted under a Board Resolution. In the case
of Securities of a Series to be issued from time to time, the Board Resolution,
Officers' Certificate or supplemental indenture may provide for the method by
which specified terms (such as interest rate, maturity date, record date or date
from which interest shall accrue) are to be determined. Securities may differ
between Series in respect of any matters, provided that all Series of Securities
shall be equally and ratably entitled to the benefits of the Indenture.

         Section 2.2.      Establishment of Terms of Series of Securities.

                  At or prior to the issuance of any Securities within a Series,
the following shall be established (as to the Series generally, in the case of
Subsection 2.2.1 and either as to such Securities within the Series or as to the
Series generally in the case of Subsections 2.2.2 through 2.2.22) by a Board
Resolution, a supplemental indenture or an Officers' Certificate pursuant to
authority granted under a Board Resolution:

                                       7

<PAGE>

                  2.2.1.   the title of the Series (which shall distinguish the
Securities of that particular Series from the Securities of any other Series);

                  2.2.2.   the price or prices (expressed as a percentage of the
principal amount thereof) at which the Securities of the Series will be issued;

                  2.2.3.   any limit upon the aggregate principal amount of the
Securities of the Series which may be authenticated and delivered under this
Indenture (except for Securities authenticated and delivered upon registration
of transfer of, or in exchange for, or in lieu of, other Securities of the
Series pursuant to Section 2.7, 2.8, 2.11, 3.6 or 9.6);

                  2.2.4.   the date or dates on which the principal of the
Securities of the Series is payable;

                  2.2.5.   the rate or rates (which may be fixed or variable)
per annum or, if applicable, the method used to determine such rate or rates
(including, but not limited to, any commodity, commodity index, stock exchange
index or financial index) at which the Securities of the Series shall bear
interest, if any, the date or dates from which such interest, if any, shall
accrue, the date or dates on which such interest, if any, shall commence and be
payable and any regular record date for the interest payable on any interest
payment date;

                  2.2.6.   the place or places where the principal of and
interest, if any, on the Securities of the Series shall be payable, or the
method of such payment, if by wire transfer, mail or other means;

                  2.2.7.   if applicable, the period or periods within which,
the price or prices at which and the terms and conditions upon which the
Securities of the Series may be redeemed, in whole or in part, at the option of
the Company;

                  2.2.8.   the obligation, if any, of the Company to redeem or
purchase the Securities of the Series pursuant to any sinking fund or analogous
provisions or at the option of a Holder thereof and the period or periods within
which, the price or prices at which and the terms and conditions upon which
Securities of the Series shall be redeemed or purchased, in whole or in part,
pursuant to such obligation;

                  2.2.9.   the dates, if any, on which and the price or prices
at which the Securities of the Series will be repurchased by the Company at the
option of the Holders thereof and other detailed terms and provisions of such
repurchase obligations;

                  2.2.10.  if other than denominations of $1,000 and any
integral multiple thereof, the denominations in which the Securities of the
Series shall be issuable;

                  2.2.11.  the forms of the Securities of the Series in bearer
or fully registered form (and, if in fully registered form, whether the
Securities will be issuable as Global Securities);

                                       8

<PAGE>

                  2.2.12.  if other than the principal amount thereof, the
portion of the principal amount of the Securities of the Series that shall be
payable upon declaration of acceleration of the maturity thereof pursuant to
Section 6.2;

                  2.2.13.  the currency of denomination of the Securities of the
Series, which may be Dollars or any Foreign Currency, including, but not limited
to, the ECU, and if such currency of denomination is a composite currency other
than the ECU, the agency or organization, if any, responsible for overseeing
such composite currency;

                  2.2.14.  the designation of the currency, currencies or
currency units in which payment of the principal of and interest, if any, on the
Securities of the Series will be made;

                  2.2.15.  if payments of principal of or interest, if any, on
the Securities of the Series are to be made in one or more currencies or
currency units other than that or those in which such Securities are
denominated, the manner in which the exchange rate with respect to such payments
will be determined;

                  2.2.16.  the manner in which the amounts of payment of
principal of or interest, if any, on the Securities of the Series will be
determined, if such amounts may be determined by reference to an index based on
a currency or currencies or by reference to a commodity, commodity index, stock
exchange index or financial index;

                  2.2.17.  the provisions, if any, relating to any security
provided for the Securities of the Series;

                  2.2.18.  if the holders of Securities of the Series may
convert or exchange the Securities into or for securities of the Issuer or of
other entities or other property, the period or periods within which, the rate
or rates at which and the terms and conditions upon which Securities of the
Series may be converted or exchanged, in whole or in part;

                  2.2.19.  any addition to or change in the Events of Default
which applies to any Securities of the Series and any change in the right of the
Trustee or the requisite Holders of such Securities to declare the principal
amount thereof due and payable pursuant to Section 6.2;

                  2.2.20.  any addition to or change in the covenants set forth
in Articles IV or V which applies to Securities of the Series;

                  2.2.21.  any other terms of the Securities of the Series
(which terms shall not be inconsistent with the provisions of this Indenture,
except as permitted by Section 9.1, but which may modify or delete any provision
of this Indenture insofar as it applies to such Series); and

                  2.2.22.  any depositories, interest rate calculation agents,
exchange rate calculation agents or other agents with respect to Securities of
such Series if other than those appointed herein.

                  All Securities of any one Series need not be issued at the
same time and may be issued from time to time, consistent with the terms of this
Indenture, if so provided by or

                                       9

<PAGE>

pursuant to the Board Resolution, supplemental indenture or Officers'
Certificate referred to above, and the authorized principal amount of any Series
may not be increased to provide for issuances of additional Securities of such
Series, unless otherwise provided in such Board Resolution, supplemental
indenture or Officers' Certificate.

         Section 2.3.      Execution and Authentication.

                  Two Officers shall sign the Securities for the Company by
manual or facsimile signature.

                  If an Officer whose signature is on a Security no longer holds
that office at the time the Security is authenticated, the Security shall
nevertheless be valid.

                  A Security shall not be valid until authenticated by the
manual signature of the Trustee or an authenticating agent. The signature shall
be conclusive evidence that the Security has been authenticated under this
Indenture.

                  The Trustee shall at any time, and from time to time,
authenticate Securities for original issue in the principal amount provided in
the Board Resolution, supplemental indenture hereto or Officers' Certificate,
upon receipt by the Trustee of a Company Order. Such Company Order may authorize
authentication and delivery pursuant to oral or electronic instructions from the
Company or its duly authorized agent or agents, which oral instructions shall be
promptly confirmed in writing. Each Security shall be dated the date of its
authentication unless otherwise provided by a Board Resolution, a supplemental
indenture hereto or an Officers' Certificate.

                  The aggregate principal amount of Securities of any Series
outstanding at any time may not exceed any limit upon the maximum principal
amount for such Series set forth in the Board Resolution, supplemental indenture
hereto or Officers' Certificate delivered pursuant to Section 2.2, except as
provided in Section 2.8.

                  Prior to the issuance of Securities of any Series, the Trustee
shall have received and (subject to Section 7.2) shall be fully protected in
relying on: (a) the Board Resolution, supplemental indenture hereto or Officers'
Certificate establishing the form of the Securities of that Series or of
Securities within that Series and the terms of the Securities of that Series or
of Securities within that Series, (b) an Officers' Certificate complying with
Section 10.4, and (c) an Opinion of Counsel complying with Section 10.4.

                  The Trustee shall have the right to decline to authenticate
and deliver any Securities of such Series: (a) if the Trustee, being advised by
counsel, determines that such action may not lawfully be taken; or (b) if the
Trustee in good faith by its board of directors or trustees, executive committee
or a trust committee of directors and/or vice-presidents shall determine that
such action would expose the Trustee to personal liability to Holders of any
then outstanding Series of Securities.

                  The Trustee may appoint an authenticating agent acceptable to
the Company to authenticate Securities. An authenticating agent may authenticate
Securities whenever the Trustee may do so. Each reference in this Indenture to
authentication by the Trustee includes

                                       10

<PAGE>

authentication by such agent. An authenticating agent has the same rights as an
Agent to deal with the Company or an Affiliate.

         Section 2.4.      Registrar and Paying Agent.

                  The Company shall maintain, with respect to each Series of
Securities, at the place or places specified with respect to such Series
pursuant to Section 2.2, an office or agency where Securities of such Series may
be presented or surrendered for payment ("Paying Agent"), where Securities of
such Series may be surrendered for registration of transfer or exchange
("Registrar") and where notices and demands to or upon the Company in respect of
the Securities of such Series and this Indenture may be served ("Service
Agent"). The Registrar shall keep a register with respect to each Series of
Securities and to their transfer and exchange. The Company will give prompt
written notice to the Trustee of the name and address, and any change in the
name or address, of each Registrar, Paying Agent or Service Agent. If at any
time the Company shall fail to maintain any such required Registrar, Paying
Agent or Service Agent or shall fail to furnish the Trustee with the name and
address thereof, such presentations, surrenders, notices and demands may be made
or served at the Corporate Trust Office of the Trustee, and the Company hereby
appoints the Trustee as its agent to receive all such presentations, surrenders,
notices and demands.

                  The Company may also from time to time designate one or more
co-registrars, additional paying agents or additional service agents and may
from time to time rescind such designations; provided, however, that no such
designation or rescission shall in any manner relieve the Company of its
obligations to maintain a Registrar, Paying Agent and Service Agent in each
place so specified pursuant to Section 2.2 for Securities of any Series for such
purposes. The Company will give prompt written notice to the Trustee of any such
designation or rescission and of any change in the name or address of any such
co-registrar, additional paying agent or additional service agent. The term
"Registrar" includes any co-registrar; the term "Paying Agent" includes any
additional paying agent; and the term "Service Agent" includes any additional
service agent.

                  The Company hereby appoints the Trustee the initial Registrar,
Paying Agent and Service Agent for each Series unless another Registrar, Paying
Agent or Service Agent, as the case may be, is appointed prior to the time
Securities of that Series are first issued.

         Section 2.5.      Paying Agent to Hold Money in Trust.

                  The Company shall require each Paying Agent other than the
Trustee to agree in writing that the Paying Agent will hold in trust, for the
benefit of Securityholders of any Series of Securities, or the Trustee, all
money held by the Paying Agent for the payment of principal of or interest on
the Series of Securities, and will notify the Trustee of any default by the
Company in making any such payment. While any such default continues, the
Trustee may require a Paying Agent to pay all money held by it to the Trustee.
The Company at any time may require a Paying Agent to pay all money held by it
to the Trustee. Upon payment over to the Trustee, the Paying Agent (if other
than the Company or a Subsidiary) shall have no further liability for the money.
If the Company or a Subsidiary acts as Paying Agent, it shall segregate and hold
in a

                                       11

<PAGE>

separate trust fund for the benefit of Securityholders of any Series of
Securities all money held by it as Paying Agent.

         Section 2.6.      Securityholder Lists.

                  The Trustee shall preserve in as current a form as is
reasonably practicable the most recent list available to it of the names and
addresses of Securityholders of each Series of Securities and shall otherwise
comply with TIA Section 312(a). If the Trustee is not the Registrar, the Company
shall furnish to the Trustee at least ten days before each interest payment date
and at such other times as the Trustee may request in writing a list, in such
form and as of such date as the Trustee may reasonably require, of the names and
addresses of Securityholders of each Series of Securities.

         Section 2.7.      Transfer and Exchange.

                  Where Securities of a Series are presented to the Registrar or
a co-registrar with a request to register a transfer or to exchange them for an
equal principal amount of Securities of the same Series, the Registrar shall
register the transfer or make the exchange if its requirements for such
transactions are met. To permit registrations of transfers and exchanges, the
Trustee shall authenticate Securities at the Registrar's request. No service
charge shall be made for any registration of transfer or exchange (except as
otherwise expressly permitted herein), but the Company may require payment of a
sum sufficient to cover any transfer tax or similar governmental charge payable
in connection therewith (other than any such transfer tax or similar
governmental charge payable upon exchanges pursuant to Sections 2.11, 3.6 or
9.6).

                  Neither the Company nor the Registrar shall be required (a) to
issue, register the transfer of, or exchange Securities of any Series for the
period beginning at the opening of business fifteen days immediately preceding
the mailing of a notice of redemption of Securities of that Series selected for
redemption and ending at the close of business on the day of such mailing, or
(b) to register the transfer of or exchange Securities of any Series selected,
called or being called for redemption as a whole or the portion being redeemed
of any such Securities selected, called or being called for redemption in part.

         Section 2.8.      Mutilated, Destroyed, Lost and Stolen Securities.

                  If any mutilated Security is surrendered to the Trustee, the
Company shall execute and the Trustee shall authenticate and deliver in exchange
therefor a new Security of the same Series and of like tenor and principal
amount and bearing a number not contemporaneously outstanding.

                  If there shall be delivered to the Company and the Trustee (i)
evidence to their satisfaction of the destruction, loss or theft of any Security
and (ii) such security or indemnity as may be required by them to save each of
them and any agent of either of them harmless, then, in the absence of notice to
the Company or the Trustee that such Security has been acquired by a bona fide
purchaser, the Company shall execute and upon its request the Trustee shall
authenticate and make available for delivery, in lieu of any such destroyed,
lost or stolen Security, a new Security of the same Series and of like tenor and
principal amount and bearing a number not contemporaneously outstanding.

                                       12

<PAGE>

                  In case any such mutilated, destroyed, lost or stolen Security
has become or is about to become due and payable, the Company in its discretion
may, instead of issuing a new Security, pay such Security.

                  Upon the issuance of any new Security under this Section, the
Company may require the payment of a sum sufficient to cover any tax or other
governmental charge that may be imposed in relation thereto and any other
expenses (including the fees and expenses of the Trustee) connected therewith.

                  Every new Security of any Series issued pursuant to this
Section in lieu of any destroyed, lost or stolen Security shall constitute an
original additional contractual obligation of the Company, whether or not the
destroyed, lost or stolen Security shall be at any time enforceable by anyone,
and shall be entitled to all the benefits of this Indenture equally and
proportionately with any and all other Securities of that Series duly issued
hereunder.

                  The provisions of this Section are exclusive and shall
preclude (to the extent lawful) all other rights and remedies with respect to
the replacement or payment of mutilated, destroyed, lost or stolen Securities.

         Section 2.9.      Outstanding Securities.

                  The Securities outstanding at any time are all the Securities
authenticated by the Trustee except for those canceled by it, those delivered to
it for cancellation, those reductions in the interest on a Global Security
effected by the Trustee in accordance with the provisions hereof and those
described in this Section as not outstanding.

                  If a Security is replaced pursuant to Section 2.8, it ceases
to be outstanding until the Trustee receives proof satisfactory to it that the
replaced Security is held by a bona fide purchaser.

                  If the Paying Agent (other than the Company, a Subsidiary or
an Affiliate of any thereof) holds on the Maturity of Securities of a Series
money sufficient to pay such Securities payable on that date, then on and after
that date such Securities of the Series cease to be outstanding and interest on
them ceases to accrue.

                  A Security does not cease to be outstanding because the
Company or an Affiliate holds the Security.

                  In determining whether the Holders of the requisite principal
amount of outstanding Securities have given any request, demand, authorization,
direction, notice, consent or waiver hereunder, the principal amount of a
Discount Security that shall be deemed to be outstanding for such purposes shall
be the amount of the principal thereof that would be due and payable as of the
date of such determination upon a declaration of acceleration of the Maturity
thereof pursuant to Section 6.2.

                                       13

<PAGE>

         Section 2.10.     Treasury Securities.

                  In determining whether the Holders of the required principal
amount of Securities of a Series have concurred in any request, demand,
authorization, direction, notice, consent or waiver Securities of a Series owned
by the Company or an Affiliate shall be disregarded, except that for the
purposes of determining whether the Trustee shall be protected in relying on any
such request, demand, authorization, direction, notice, consent or waiver only
Securities of a Series that the Trustee knows are so owned shall be so
disregarded.

         Section 2.11.     Temporary Securities.

                  Until definitive Securities are ready for delivery, the
Company may prepare and the Trustee shall authenticate temporary Securities upon
a Company Order. Temporary Securities shall be substantially in the form of
definitive Securities but may have variations that the Company considers
appropriate for temporary Securities. Without unreasonable delay, the Company
shall prepare and the Trustee upon request shall authenticate definitive
Securities of the same Series and date of maturity in exchange for temporary
Securities. Until so exchanged, temporary securities shall have the same rights
under this Indenture as the definitive Securities.

         Section 2.12.     Cancellation.

                  The Company at any time may deliver Securities to the Trustee
for cancellation. The Registrar and the Paying Agent shall forward to the
Trustee any Securities surrendered to them for registration of transfer,
exchange or payment. The Trustee shall cancel all Securities surrendered for
transfer, exchange, payment, replacement or cancellation and shall destroy such
canceled Securities (subject to the record retention requirement of the Exchange
Act) and deliver a certificate of such destruction to the Company, unless the
Company otherwise directs. The Company may not issue new Securities to replace
Securities that it has paid or delivered to the Trustee for cancellation.

         Section 2.13.     Defaulted Interest.

                  If the Company defaults in a payment of interest on a Series
of Securities, it shall pay the defaulted interest, plus, to the extent
permitted by law, any interest payable on the defaulted interest, to the persons
who are Securityholders of the Series on a subsequent special record date. The
Company shall fix the record date and payment date. At least 30 days before the
record date, the Company shall mail to the Trustee and to each Securityholder of
the Series a notice that states the record date, the payment date and the amount
of interest to be paid. The Company may pay defaulted interest in any other
lawful manner.

         Section 2.14.     Global Securities.

                  2.14.1.  Terms of Securities. A Board Resolution, a
supplemental indenture hereto or an Officers' Certificate shall establish
whether the Securities of a Series shall be issued in whole or in part in the
form of one or more Global Securities and the Depository for such Global
Security or Securities.

                                       14

<PAGE>

                  2.14.2.  Transfer and Exchange. Notwithstanding any provisions
to the contrary contained in Section 2.7 of the Indenture and in addition
thereto, any Global Security shall be exchangeable pursuant to Section 2.7 of
the Indenture for Securities registered in the names of Holders other than the
Depository for such Security or its nominee only if (i) such Depository notifies
the Company that it is unwilling or unable to continue as Depository for such
Global Security or if at any time such Depository ceases to be a clearing agency
registered under the Exchange Act, and, in either case, the Company fails to
appoint a successor Depository within 90 days of such event, (ii) the Company
executes and delivers to the Trustee an Officers' Certificate to the effect that
such Global Security shall be so exchangeable or (iii) an Event of Default with
respect to the Securities represented by such Global Security shall have
happened and be continuing. Any Global Security that is exchangeable pursuant to
the preceding sentence shall be exchangeable for Securities registered in such
names as the Depository shall direct in writing in an aggregate principal amount
equal to the principal amount of the Global Security with like tenor and terms.

                  Except as provided in this Section 2.14.2, a Global Security
may not be transferred except as a whole by the Depository with respect to such
Global Security to a nominee of such Depository, by a nominee of such Depository
to such Depository or another nominee of such Depository or by the Depository or
any such nominee to a successor Depository or a nominee of such a successor
Depository.

                  2.14.3.  Legend. Unless otherwise provided pursuant to Section
2.2, any Global Security issued hereunder shall bear a legend in substantially
the following form:

                  "This Security is a Global Security within the meaning of the
Indenture hereinafter referred to and is registered in the name of the
Depository or a nominee of the Depository. This Security is exchangeable for
Securities registered in the name of a person other than the Depository or its
nominee only in the limited circumstances described in the Indenture, and may
not be transferred except as a whole by the Depository to a nominee of the
Depository, by a nominee of the Depository to the Depository or another nominee
of the Depository or by the Depository or any such nominee to a successor
Depository or a nominee of such a successor Depository."

                  2.14.4.  Acts of Holders. The Depository, as a Holder, may
appoint agents and otherwise authorize participants to give or take any request,
demand, authorization, direction, notice, consent, waiver or other action which
a Holder is entitled to give or take under the Indenture.

                  2.14.5.  Payments. Notwithstanding the other provisions of
this Indenture, unless otherwise specified as contemplated by Section 2.2,
payment of the principal of, premium, if any, and interest, if any, on any
Global Security shall be made to the Holder thereof.

                  2.14.6.  Consents, Declaration and Directions. Except as
provided in Section 2.14.5, the Company, the Trustee and any Agent shall treat a
person as the Holder of such principal amount of outstanding Securities of such
Series represented by a Global Security as shall be specified in a written
statement of the Depositary with respect to such Global Security,

                                       15

<PAGE>

for purposes of obtaining any consents, declarations, waivers or directions
required to be given by the Holders pursuant to this Indenture.

         Section 2.15.     CUSIP Numbers.

                  The Company in issuing the Securities may use "CUSIP" numbers
(if then generally in use), and, if so, the Trustee shall use "CUSIP" numbers in
notices of redemption as a convenience to Holders; provided that any such notice
may state that no representation is made as to the correctness of such numbers
either as printed on the Securities or as contained in any notice of a
redemption and that reliance may be placed only on the other elements of
identification printed on the Securities, and any such redemption shall not be
affected by any defect in or omission of such numbers.

                                  ARTICLE III.
                                   REDEMPTION

         Section 3.1.      Notice to Trustee.

                  The Company may, with respect to any Series of Securities,
reserve the right to redeem and pay the Series of Securities or may covenant to
redeem and pay the Series of Securities or any part thereof prior to the Stated
Maturity thereof at such time and on such terms as provided for in such
Securities. If a Series of Securities is redeemable and the Company wants or is
obligated to redeem prior to the Stated Maturity thereof all or part of the
Series of Securities pursuant to the terms of such Securities, it shall notify
the Trustee of the redemption date and the principal amount of Series of
Securities to be redeemed. The Company shall give the notice at least 45 days
before the redemption date (or such shorter notice as may be acceptable to the
Trustee).

         Section 3.2.      Selection of Securities to be Redeemed.

                  Unless otherwise indicated for a particular Series by a Board
Resolution, a supplemental indenture or an Officers' Certificate, if less than
all the Securities of a Series are to be redeemed, the Trustee shall select the
Securities of the Series to be redeemed in any manner that the Trustee deems
fair and appropriate. The Trustee shall make the selection from Securities of
the Series outstanding not previously called for redemption. The Trustee may
select for redemption portions of the principal of Securities of the Series that
have denominations larger than $1,000. Securities of the Series and portions of
them it selects shall be in amounts of $1,000 or whole multiples of $1,000 or,
with respect to Securities of any Series issuable in other denominations
pursuant to Section 2.2.10, the minimum principal denomination for each Series
and integral multiples thereof. Provisions of this Indenture that apply to
Securities of a Series called for redemption also apply to portions of
Securities of that Series called for redemption.

         Section 3.3.      Notice of Redemption.

                  Unless otherwise indicated for a particular Series by Board
Resolution, a supplemental indenture hereto or an Officers' Certificate, at
least 30 days but not more than 60 days before a redemption date, the Company
shall mail a notice of redemption by first-class mail

                                       16

<PAGE>

to each Holder whose Securities are to be redeemed and if any Bearer Securities
are outstanding, publish on one occasion a notice in an Authorized Newspaper.

                  The notice shall identify the Securities of the Series to be
redeemed and shall state:

                  (a)      the redemption date;

                  (b)      the redemption price;

                  (c)      the name and address of the Paying Agent;

                  (d)      that Securities of the Series called for redemption
         must be surrendered to the Paying Agent to collect the redemption
         price;

                  (e)      that interest on Securities of the Series called for
         redemption ceases to accrue on and after the redemption date; and

                  (f)      any other information as may be required by the terms
         of the particular Series or the Securities of a Series being redeemed.

                  At the Company's request, the Trustee shall give the notice of
redemption in the Company's name and at its expense.

         Section 3.4.      Effect of Notice of Redemption.

                  Once notice of redemption is mailed or published as provided
in Section 3.3, Securities of a Series called for redemption become due and
payable on the redemption date and at the redemption price. A notice of
redemption may not be conditional. Upon surrender to the Paying Agent, such
Securities shall be paid at the redemption price plus accrued interest to the
redemption date.

         Section 3.5.      Deposit of Redemption Price.

                  On or before the redemption date, the Company shall deposit
with the Paying Agent money sufficient to pay the redemption price of and
accrued interest, if any, on all Securities to be redeemed on that date.

         Section 3.6.      Securities Redeemed in Part.

                  Upon surrender of a Security that is redeemed in part, the
Trustee shall authenticate for the Holder a new Security of the same Series and
the same maturity equal in principal amount to the unredeemed portion of the
Security surrendered.

                                       17

<PAGE>


                                   ARTICLE IV.
                                    COVENANTS

         Section 4.1.      Payment of Principal and Interest.

                  The Company covenants and agrees for the benefit of the
Holders of each Series of Securities that it will duly and punctually pay the
principal of and interest, if any, on the Securities of that Series in
accordance with the terms of such Securities and this Indenture.

         Section 4.2.      SEC Reports.

                  The Company shall deliver to the Trustee within 15 days after
it files them with the SEC copies of the annual reports and of the information,
documents, and other reports (or copies of such portions of any of the foregoing
as the SEC may by rules and regulations prescribe) which the Company is required
to file with the SEC pursuant to Section 13 or 15(d) of the Exchange Act. The
Company also shall comply with the other provisions of TIA Section 314(a).

         Section 4.3.      Compliance Certificate.

                  The Company shall deliver to the Trustee, within 90 days after
the end of each fiscal year of the Company, an Officers' Certificate stating
that a review of the activities of the Company and its Subsidiaries during the
preceding fiscal year has been made under the supervision of the signing
Officers with a view to determining whether the Company has kept, observed,
performed and fulfilled its obligations under this Indenture, and further
stating, as to each such Officer signing such certificate, that to the best of
his knowledge the Company has kept, observed, performed and fulfilled each and
every covenant contained in this Indenture and is not in default in the
performance or observance of any of the terms, provisions and conditions hereof
(or, if a Default or Event of Default shall have occurred, describing all such
Defaults or Events of Default of which he may have knowledge).

                  The Company will, so long as any of the Securities are
outstanding, deliver to the Trustee, forthwith upon becoming aware of any
Default or Event of Default, an Officers' Certificate specifying such Default or
Event of Default and what action the Company is taking or proposes to take with
respect thereto.

         Section 4.4.      Stay, Extension and Usury Laws.

                  The Company covenants (to the extent that it may lawfully do
so) that it will not at any time insist upon, plead, or in any manner whatsoever
claim or take the benefit or advantage of, any stay, extension or usury law
wherever enacted, now or at any time hereafter in force, which may affect the
covenants or the performance of this Indenture or the Securities; and the
Company (to the extent it may lawfully do so) hereby expressly waives all
benefit or advantage of any such law and covenants that it will not, by resort
to any such law, hinder, delay or impede the execution of any power herein
granted to the Trustee, but will suffer and permit the execution of every such
power as though no such law has been enacted.

                                       18

<PAGE>

         Section 4.5.      Corporate Existence.

                  Subject to Article V, the Company will do or cause to be done
all things necessary to preserve and keep in full force and effect its corporate
existence and the corporate, partnership or other existence of each Significant
Subsidiary in accordance with the respective organizational documents of each
Significant Subsidiary and the rights (charter and statutory), licenses and
franchises of the Company and its Significant Subsidiaries; provided, however,
that the Company shall not be required to preserve any such right, license or
franchise, or the corporate, partnership or other existence of any Significant
Subsidiary, if the Board of Directors shall determine that the preservation
thereof is no longer desirable in the conduct of the business of the Company and
its Subsidiaries taken as a whole and that the loss thereof is not adverse in
any material respect to the Holders.

         Section 4.6.      Taxes.

                  The Company shall, and shall cause each of its Significant
Subsidiaries to, pay prior to delinquency all taxes, assessments and
governmental levies, except as contested in good faith and by appropriate
proceedings.

                                   ARTICLE V.
                                   SUCCESSORS

         Section 5.1.      When Company May Merge, Etc.

                  The Company shall not consolidate with or merge into, or
convey, transfer or lease all or substantially all of its properties and assets
to, any person (a "successor person"), and may not permit any person to merge
into, or convey, transfer or lease its properties and assets substantially as an
entirety to, the Company, unless:

                  (a)      the successor person (if any) is a corporation,
         partnership, trust or other entity organized and validly existing under
         the laws of any U.S. domestic jurisdiction and expressly assumes the
         Company's obligations on the Securities and under this Indenture and

                  (b)      immediately after giving effect to the transaction,
         no Default or Event of Default, shall have occurred and be continuing.

                  The Company shall deliver to the Trustee prior to the
consummation of the proposed transaction an Officers' Certificate to the
foregoing effect and an Opinion of Counsel stating that the proposed transaction
and such supplemental indenture comply with this Indenture.

         Section 5.2.      Successor Corporation Substituted.

                  Upon any consolidation or merger, or any sale, lease,
conveyance or other disposition of all or substantially all of the assets of the
Company in accordance with Section 5.1, the successor corporation formed by such
consolidation or into or with which the Company is merged or to which such sale,
lease, conveyance or other disposition is made shall succeed to,

                                       19

<PAGE>

and be substituted for, and may exercise every right and power of, the Company
under this Indenture with the same effect as if such successor person has been
named as the Company herein; provided, however, that the predecessor Company in
the case of a sale, lease, conveyance or other disposition shall not be released
from the obligation to pay the principal of and interest, if any, on the
Securities.

                                   ARTICLE VI.
                              DEFAULTS AND REMEDIES

         Section 6.1.      Events of Default.

                  "Event of Default," wherever used herein with respect to
Securities of any Series, means any one of the following events, unless in the
establishing Board Resolution, supplemental indenture or Officers' Certificate,
it is provided that such Series shall not have the benefit of said Event of
Default:

                  (a)      default in the payment of any interest on any
         Security of that Series when it becomes due and payable, and
         continuance of such default for a period of 30 days (unless the entire
         amount of such payment is deposited by the Company with the Trustee or
         with a Paying Agent prior to the expiration of such period of 30 days);
         or

                  (b)      default in the payment of the principal of any
         Security of that Series at its Maturity; or

                  (c)      default in the deposit of any sinking fund payment,
         when and as due in respect of any Security of that Series; or

                  (d)      default in the performance or breach of any covenant
         or warranty of the Company in this Indenture (other than a covenant or
         warranty that has been included in this Indenture solely for the
         benefit of Series of Securities other than that Series), which default
         continues uncured for a period of 60 days after there has been given,
         by registered or certified mail, to the Company by the Trustee or to
         the Company and the Trustee by the Holders of at least 25% in principal
         amount of the outstanding Securities of that Series a written notice
         specifying such default or breach and requiring it to be remedied and
         stating that such notice is a "Notice of Default" hereunder; or

                  (e)      the Company or any of its Significant Subsidiaries
         pursuant to or within the meaning of any Bankruptcy Law:

                           (i)      commences a voluntary case,

                           (ii)     consents to the entry of an order for relief
                  against it in an involuntary case,

                           (iii)    consents to the appointment of a Custodian
                  of it or for all or substantially all of its property,

                           (iv)     makes a general assignment for the benefit
                  of its creditors, or

                                       20

<PAGE>

                           (v)      generally is unable to pay its debts as the
                  same become due; or

                  (f)      a court of competent jurisdiction enters an order or
         decree under any Bankruptcy Law that:

                           (i)      is for relief against the Company or any of
                  its Significant Subsidiaries in an involuntary case,

                           (ii)     appoints a Custodian of the Company or any
                  of its Significant Subsidiaries or for all or substantially
                  all of its property, or

                           (iii)    orders the liquidation of the Company or any
                  of its Significant Subsidiaries,

         and the order or decree remains unstayed and in effect for 60 days; or

                  (g)      any other Event of Default provided with respect to
         Securities of that Series, which is specified in a Board Resolution, a
         supplemental indenture hereto or an Officers' Certificate, in
         accordance with Section 2.2.19.

                  The term "Bankruptcy Law" means title 11, U.S. Code or any
similar Federal or State law for the relief of debtors. The term "Custodian"
means any receiver, trustee, assignee, liquidator or similar official under any
Bankruptcy Law.

         Section 6.2.      Acceleration of Maturity; Rescission and Annulment.

                  If an Event of Default with respect to Securities of any
Series at the time outstanding occurs and is continuing (other than an Event of
Default referred to in Section 6.1(e) or (f)) then in every such case the
Trustee or the Holders of not less than 25% in principal amount of the
outstanding Securities of that Series may declare the principal amount (or, if
any Securities of that Series are Discount Securities, such portion of the
principal amount as may be specified in the terms of such Securities) of and
accrued and unpaid interest, if any, on all of the Securities of that Series to
be due and payable immediately, by a notice in writing to the Company (and to
the Trustee if given by Holders), and upon any such declaration such principal
amount (or specified amount) and accrued and unpaid interest, if any, shall
become immediately due and payable. If an Event of Default specified in Section
6.1(e) or (f) shall occur, the principal amount (or specified amount) of and
accrued and unpaid interest, if any, on all outstanding Securities shall ipso
facto become and be immediately due and payable without any declaration or other
act on the part of the Trustee or any Holder.

                  At any time after such a declaration of acceleration with
respect to any Series has been made and before a judgment or decree for payment
of the money due has been obtained by the Trustee as hereinafter in this Article
provided, the Holders of a majority in principal amount of the outstanding
Securities of that Series, by written notice to the Company and the Trustee, may
rescind and annul such declaration and its consequences if:

                  (a)      the Company has paid or deposited with the Trustee a
         sum sufficient to pay

                                       21

<PAGE>

                           (i)      all overdue interest, if any, on all
                  Securities of that Series,

                           (ii)     the principal of any Securities of that
                  Series which have become due otherwise than by such
                  declaration of acceleration and interest thereon at the rate
                  or rates prescribed therefor in such Securities,

                           (iii)    to the extent that payment of such interest
                  is lawful, interest upon any overdue principal and overdue
                  interest at the rate or rates prescribed therefor in such
                  Securities, and

                           (iv)     all sums paid or advanced by the Trustee
                  hereunder and the reasonable compensation, expenses,
                  disbursements and advances of the Trustee, its agents and
                  counsel;

and

                  (b)      all Events of Default with respect to Securities of
         that Series, other than the non-payment of the principal of Securities
         of that Series which have become due solely by such declaration of
         acceleration, have been cured or waived as provided in Section 6.13.

                  No such rescission shall affect any subsequent Default or
impair any right consequent thereon.

         Section 6.3.      Collection of Indebtedness and Suits for Enforcement
by Trustee.

                  The Company covenants that if

                  (a)      default is made in the payment of any interest on any
         Security when such interest becomes due and payable and such default
         continues for a period of 30 days, or

                  (b)      default is made in the payment of principal of any
         Security at the Maturity thereof, or

                  (c)      default is made in the deposit of any sinking fund
         payment when and as due by the terms of a Security,

then, the Company will, upon demand of the Trustee, pay to it, for the benefit
of the Holders of such Securities, the whole amount then due and payable on such
Securities for principal and interest and, to the extent that payment of such
interest shall be legally enforceable, interest on any overdue principal or any
overdue interest, at the rate or rates prescribed therefor in such Securities,
and, in addition thereto, such further amount as shall be sufficient to cover
the costs and expenses of collection, including the reasonable compensation,
expenses, disbursements and advances of the Trustee, its agents and counsel.

                  If the Company fails to pay such amounts forthwith upon such
demand, the Trustee, in its own name and as trustee of an express trust, may
institute a judicial proceeding for the collection of the sums so due and
unpaid, may prosecute such proceeding to judgment or

                                       22

<PAGE>

final decree and may enforce the same against the Company or any other obligor
upon such Securities and collect the moneys adjudged or deemed to be payable in
the manner provided by law out of the property of the Company or any other
obligor upon such Securities, wherever situated.

                  If an Event of Default with respect to any Securities of any
Series occurs and is continuing, the Trustee may in its discretion proceed to
protect and enforce its rights and the rights of the Holders of Securities of
such Series by such appropriate judicial proceedings as the Trustee shall deem
most effectual to protect and enforce any such rights, whether for the specific
enforcement of any covenant or agreement in this Indenture or in aid of the
exercise of any power granted herein, or to enforce any other proper remedy.

         Section 6.4.      Trustee May File Proofs of Claim.

                  In case of the pendency of any receivership, insolvency,
liquidation, bankruptcy, reorganization, arrangement, adjustment, composition or
other judicial proceeding relative to the Company or any other obligor upon the
Securities or the property of the Company or of such other obligor or their
creditors, the Trustee (irrespective of whether the principal of the Securities
shall then be due and payable as therein expressed or by declaration or
otherwise and irrespective of whether the Trustee shall have made any demand on
the Company for the payment of overdue principal or interest) shall be entitled
and empowered, by intervention in such proceeding or otherwise,

                  (a)      to file and prove a claim for the whole amount of
         principal and interest owing and unpaid in respect of the Securities
         and to file such other papers or documents as may be necessary or
         advisable in order to have the claims of the Trustee (including any
         claim for the reasonable compensation, expenses, disbursements and
         advances of the Trustee, its agents and counsel) and of the Holders
         allowed in such judicial proceeding, and

                  (b)      to collect and receive any moneys or other property
         payable or deliverable on any such claims and to distribute the same,
         and any custodian, receiver, assignee, trustee, liquidator,
         sequestrator or other similar official in any such judicial proceeding
         is hereby authorized by each Holder to make such payments to the
         Trustee and, in the event that the Trustee shall consent to the making
         of such payments directly to the Holders, to pay to the Trustee any
         amount due it for the reasonable compensation, expenses, disbursements
         and advances of the Trustee, its agents and counsel, and any other
         amounts due the Trustee under Section 7.7.

                  Nothing herein contained shall be deemed to authorize the
Trustee to authorize or consent to or accept or adopt on behalf of any Holder
any plan of reorganization, arrangement, adjustment or composition affecting the
Securities or the rights of any Holder thereof or to authorize the Trustee to
vote in respect of the claim of any Holder in any such proceeding.

         Section 6.5.      Trustee May Enforce Claims Without Possession of
Securities.

                  All rights of action and claims under this Indenture or the
Securities may be prosecuted and enforced by the Trustee without the possession
of any of the Securities or the

                                       23

<PAGE>

production thereof in any proceeding relating thereto, and any such proceeding
instituted by the Trustee shall be brought in its own name as trustee of an
express trust, and any recovery of judgment shall, after provision for the
payment of the reasonable compensation, expenses, disbursements and advances of
the Trustee, its agents and counsel, be for the ratable benefit of the Holders
of the Securities in respect of which such judgment has been recovered.

         Section 6.6.      Application of Money Collected.

                  Any money collected by the Trustee pursuant to this Article
shall be applied in the following order, at the date or dates fixed by the
Trustee and, in case of the distribution of such money on account of principal
or interest, upon presentation of the Securities and the notation thereon of the
payment if only partially paid and upon surrender thereof if fully paid:

                  First:   To the payment of all amounts due the Trustee under
Section 7.7; and

                  Second:  To the payment of the amounts then due and unpaid for
principal of and interest on the Securities in respect of which or for the
benefit of which such money has been collected, ratably, without preference or
priority of any kind, according to the amounts due and payable on such
Securities for principal and interest, respectively; and

                  Third:   To the Company.

         Section 6.7.      Limitation on Suits.

                  No Holder of any Security of any Series shall have any right
to institute any proceeding, judicial or otherwise, with respect to this
Indenture, or for the appointment of a receiver or trustee, or for any other
remedy hereunder, unless

                  (a)      such Holder has previously given written notice to
         the Trustee of a continuing Event of Default with respect to the
         Securities of that Series;

                  (b)      the Holders of not less than 25% in principal amount
         of the outstanding Securities of that Series shall have made written
         request to the Trustee to institute proceedings in respect of such
         Event of Default in its own name as Trustee hereunder;

                  (c)      such Holder or Holders have offered to the Trustee
         reasonable indemnity against the costs, expenses and liabilities to be
         incurred in compliance with such request;

                  (d)      the Trustee for 60 days after its receipt of such
         notice, request and offer of indemnity has failed to institute any such
         proceeding; and

                  (e)      no direction inconsistent with such written request
         has been given to the Trustee during such 60-day period by the Holders
         of a majority in principal amount of the outstanding Securities of that
         Series;

it being understood and intended that no one or more of such Holders shall have
any right in any manner whatever by virtue of, or by availing of, any provision
of this Indenture to affect, disturb or prejudice the rights of any other of
such Holders, or to obtain or to seek to obtain priority or

                                       24

<PAGE>

preference over any other of such Holders or to enforce any right under this
Indenture, except in the manner herein provided and for the equal and ratable
benefit of all such Holders.

         Section 6.8.      Unconditional Right of Holders to Receive Principal
and Interest.

                  Notwithstanding any other provision in this Indenture, the
Holder of any Security shall have the right, which is absolute and
unconditional, to receive payment of the principal of and interest, if any, on
such Security on the Stated Maturity or Stated Maturities expressed in such
Security (or, in the case of redemption, on the redemption date) and to
institute suit for the enforcement of any such payment, and such rights shall
not be impaired without the consent of such Holder.

         Section 6.9.      Restoration of Rights and Remedies.

                  If the Trustee or any Holder has instituted any proceeding to
enforce any right or remedy under this Indenture and such proceeding has been
discontinued or abandoned for any reason, or has been determined adversely to
the Trustee or to such Holder, then and in every such case, subject to any
determination in such proceeding, the Company, the Trustee and the Holders shall
be restored severally and respectively to their former positions hereunder and
thereafter all rights and remedies of the Trustee and the Holders shall continue
as though no such proceeding had been instituted.

         Section 6.10.     Rights and Remedies Cumulative.

                  Except as otherwise provided with respect to the replacement
or payment of mutilated, destroyed, lost or stolen Securities in Section 2.8, no
right or remedy herein conferred upon or reserved to the Trustee or to the
Holders is intended to be exclusive of any other right or remedy, and every
right and remedy shall, to the extent permitted by law, be cumulative and in
addition to every other right and remedy given hereunder or now or hereafter
existing at law or in equity or otherwise. The assertion or employment of any
right or remedy hereunder, or otherwise, shall not prevent the concurrent
assertion or employment of any other appropriate right or remedy.

         Section 6.11.     Delay or Omission Not Waiver.

                  No delay or omission of the Trustee or of any Holder of any
Securities to exercise any right or remedy accruing upon any Event of Default
shall impair any such right or remedy or constitute a waiver of any such Event
of Default or an acquiescence therein. Every right and remedy given by this
Article or by law to the Trustee or to the Holders may be exercised from time to
time, and as often as may be deemed expedient, by the Trustee or by the Holders,
as the case may be.

         Section 6.12.     Control by Holders.

                  The Holders of a majority in principal amount of the
outstanding Securities of any Series shall have the right to direct the time,
method and place of conducting any proceeding for any remedy available to the
Trustee, or exercising any trust or power conferred on the Trustee, with respect
to the Securities of such Series, provided that

                                       25

<PAGE>

                  (a)      such direction shall not be in conflict with any rule
         of law or with this Indenture,

                  (b)      the Trustee may take any other action deemed proper
         by the Trustee which is not inconsistent with such direction, and

                  (c)      subject to the provisions of Section 6.1, the Trustee
         shall have the right to decline to follow any such direction if the
         Trustee in good faith shall, by a Responsible Officer of the Trustee,
         determine that the proceeding so directed would involve the Trustee in
         personal liability.

         Section 6.13.     Waiver of Past Defaults.

                  Subject to Section 6.2, the Holders of not less than a
majority in principal amount of the outstanding Securities of any Series may on
behalf of the Holders of all the Securities of such Series waive any past
Default hereunder with respect to such Series and its consequences, except a
Default in the payment of the principal of or interest on any Security of such
Series (provided, however, that the Holders of a majority in principal amount of
the outstanding Securities of any Series may rescind an acceleration and its
consequences, including any related payment default that resulted from such
acceleration). Upon any such waiver, such Default shall cease to exist, and any
Event of Default arising therefrom shall be deemed to have been cured, for every
purpose of this Indenture; but no such waiver shall extend to any subsequent or
other Default or impair any right consequent thereon.

         Section 6.14.     Undertaking for Costs.

                  All parties to this Indenture agree, and each Holder of any
Security by his acceptance thereof shall be deemed to have agreed, that any
court may in its discretion require, in any suit for the enforcement of any
right or remedy under this Indenture, or in any suit against the Trustee for any
action taken, suffered or omitted by it as Trustee, the filing by any party
litigant in such suit of an undertaking to pay the costs of such suit, and that
such court may in its discretion assess reasonable costs, including reasonable
attorneys' fees, against any party litigant in such suit, having due regard to
the merits and good faith of the claims or defenses made by such party litigant;
but the provisions of this Section shall not apply to any suit instituted by the
Company, to any suit instituted by the Trustee, to any suit instituted by any
Holder, or group of Holders, holding in the aggregate more than 10% in principal
amount of the outstanding Securities of any Series, or to any suit instituted by
any Holder for the enforcement of the payment of the principal of or interest on
any Security on or after the Stated Maturity or Stated Maturities expressed in
such Security (or, in the case of redemption, on the redemption date).

                                  ARTICLE VII.
                                     TRUSTEE

         Section 7.1.      Duties of Trustee.

                  (a)      If an Event of Default has occurred and is
         continuing, the Trustee shall exercise the rights and powers vested in
         it by this Indenture and use the same degree of

                                       26

<PAGE>

         care and skill in their exercise as a prudent man would exercise or use
         under the circumstances in the conduct of his own affairs.

                  (b)      Except during the continuance of an Event of Default:

                           (i)      The Trustee need perform only those duties
                  that are specifically set forth in this Indenture and no
                  others.

                           (ii)     In the absence of bad faith on its part, the
                  Trustee may conclusively rely, as to the truth of the
                  statements and the correctness of the opinions expressed
                  therein, upon Officers' Certificates or Opinions of Counsel
                  furnished to the Trustee and conforming to the requirements of
                  this Indenture; however, in the case of any such Officers'
                  Certificates or Opinions of Counsel which by any provisions
                  hereof are specifically required to be furnished to the
                  Trustee, the Trustee shall examine such Officers' Certificates
                  and Opinions of Counsel to determine whether or not they
                  conform to the requirements of this Indenture.

                  (c)      The Trustee may not be relieved from liability for
         its own negligent action, its own negligent failure to act or its own
         willful misconduct, except that:

                           (i)      This paragraph does not limit the effect of
                  paragraph (b) of this Section.

                           (ii)     The Trustee shall not be liable for any
                  error of judgment made in good faith by a Responsible Officer,
                  unless it is proved that the Trustee was negligent in
                  ascertaining the pertinent facts.

                           (iii)    The Trustee shall not be liable with respect
                  to any action taken, suffered or omitted to be taken by it
                  with respect to Securities of any Series in good faith in
                  accordance with the direction of the Holders of a majority in
                  principal amount of the outstanding Securities of such Series
                  relating to the time, method and place of conducting any
                  proceeding for any remedy available to the Trustee, or
                  exercising any trust or power conferred upon the Trustee,
                  under this Indenture with respect to the Securities of such
                  Series. (d) Every provision of this Indenture that in any way
                  relates to the Trustee is subject to paragraph (a), (b) and
                  (c) of this Section.

                  (e)      The Trustee may refuse to perform any duty or
         exercise any right or power unless it receives indemnity satisfactory
         to it against any loss, liability or expense.

                  (f)      The Trustee shall not be liable for interest on any
         money received by it except as the Trustee may agree in writing with
         the Company. Money held in trust by the Trustee need not be segregated
         from other funds except to the extent required by law.

                  (g)      No provision of this Indenture shall require the
         Trustee to risk its own funds or otherwise incur any financial
         liability in the performance of any of its duties, or

                                       27

<PAGE>

         in the exercise of any of its rights or powers, if it shall have
         reasonable grounds for believing that repayment of such funds or
         adequate indemnity against such risk is not reasonably assured to it.

                  (h)      The Paying Agent, the Registrar and any
         authenticating agent shall be entitled to the protections and
         immunities as are set forth in paragraphs (a), (b) and (c) of this
         Section with respect to the Trustee.

         Section 7.2.      Rights of Trustee.

                  (a)      The Trustee may rely on and shall be protected in
         acting or refraining from acting upon any document believed by it to be
         genuine and to have been signed or presented by the proper person. The
         Trustee need not investigate any fact or matter stated in the document.

                  (b)      Before the Trustee acts or refrains from acting, it
         may require an Officers' Certificate or an Opinion of Counsel. The
         Trustee shall not be liable for any action it takes or omits to take in
         good faith in reliance on such Officers' Certificate or Opinion of
         Counsel.

                  (c)      The Trustee may act through agents and shall not be
         responsible for the misconduct or negligence of any agent appointed
         with due care. No Depository shall be deemed an agent of the Trustee
         and the Trustee shall not be responsible for any act or omission by any
         Depository.

                  (d)      The Trustee shall not be liable for any action it
         takes or omits to take in good faith which it believes to be authorized
         or within its rights or powers.

                  (e)      The Trustee may consult with counsel and the advice
         of such counsel or any Opinion of Counsel shall be full and complete
         authorization and protection in respect of any action taken, suffered
         or omitted by it hereunder in good faith and in reliance thereon.

                  (f)      The Trustee shall be under no obligation to exercise
         any of the rights or powers vested in it by this Indenture at the
         request or direction of any of the Holders of Securities unless such
         Holders shall have offered to the Trustee reasonable security or
         indemnity against the costs, expenses and liabilities which might be
         incurred by it in compliance with such request or direction.

         Section 7.3.      Individual Rights of Trustee.

                  The Trustee in its individual or any other capacity may become
the owner or pledgee of Securities and may otherwise deal with the Company or an
Affiliate with the same rights it would have if it were not Trustee. Any Agent
may do the same with like rights. The Trustee is also subject to Sections 7.10
and 7.11.

         Section 7.4.      Trustee's Disclaimer.

                                       28

<PAGE>

                  The Trustee makes no representation as to the validity or
adequacy of this Indenture or the Securities, it shall not be accountable for
the Company's use of the proceeds from the Securities, and it shall not be
responsible for any statement in the Securities other than its authentication.

         Section 7.5.      Notice of Defaults.

                  If a Default or Event of Default occurs and is continuing with
respect to the Securities of any Series and if it is known to a Responsible
Officer of the Trustee, the Trustee shall mail to each Securityholder of the
Securities of that Series and, if any Bearer Securities are outstanding, publish
on one occasion in an Authorized Newspaper, notice of a Default or Event of
Default within 90 days after it occurs or, if later, after a Responsible Officer
of the Trustee has knowledge of such Default or Event of Default. Except in the
case of a Default or Event of Default in payment of principal of or interest on
any Security of any Series, the Trustee may withhold the notice if and so long
as its corporate trust committee or a committee of its Responsible Officers in
good faith determines that withholding the notice is in the interests of
Securityholders of that Series.

         Section 7.6.      Reports by Trustee to Holders.

                  Within 60 days after May 15 in each year, the Trustee shall
transmit by mail to all Securityholders, as their names and addresses appear on
the register kept by the Registrar and, if any Bearer Securities are
outstanding, publish in an Authorized Newspaper, a brief report dated as of such
May 15, in accordance with, and to the extent required under, TIA Section 313.

                  A copy of each report at the time of its mailing to
Securityholders of any Series shall be filed with the SEC and each stock
exchange on which the Securities of that Series are listed. The Company shall
promptly notify the Trustee when Securities of any Series are listed on any
stock exchange.

         Section 7.7.      Compensation and Indemnity.

                  The Company shall pay to the Trustee from time to time
reasonable compensation for its services. The Trustee's compensation shall not
be limited by any law on compensation of a trustee of an express trust. The
Company shall reimburse the Trustee upon request for all reasonable
out-of-pocket expenses incurred by it. Such expenses shall include the
reasonable compensation and expenses of the Trustee's agents and counsel.

                  The Company shall indemnify the Trustee (including the cost of
defending itself) against any loss, liability or expense incurred by it except
as set forth in the next paragraph in the performance of its duties under this
Indenture as Trustee or Agent. The Trustee shall notify the Company promptly of
any claim for which it may seek indemnity. The Company shall defend the claim
and the Trustee shall cooperate in the defense. The Trustee may have separate
counsel and the Company shall pay the reasonable fees and expenses of such
counsel. The Company need not pay for any settlement made without its consent,
which consent shall not be unreasonably withheld. This indemnification shall
apply to officers, directors, employees, shareholders and agents of the Trustee.

                                       29

<PAGE>

                  The Company need not reimburse any expense or indemnify
against any loss or liability incurred by the Trustee or by any officer,
director, employee, shareholder or agent of the Trustee through negligence or
bad faith.

                  To secure the Company's payment obligations in this Section,
the Trustee shall have a lien prior to the Securities of any Series on all money
or property held or collected by the Trustee, except that held in trust to pay
principal and interest on particular Securities of that Series.

                  When the Trustee incurs expenses or renders services after an
Event of Default specified in Section 6.1(e) or (f) occurs, the expenses and the
compensation for the services are intended to constitute expenses of
administration under any Bankruptcy Law.

         Section 7.8.      Replacement of Trustee.

                  A resignation or removal of the Trustee and appointment of a
successor Trustee shall become effective only upon the successor Trustee's
acceptance of appointment as provided in this Section.

                  The Trustee may resign with respect to the Securities of one
or more Series by so notifying the Company. The Holders of a majority in
principal amount of the Securities of any Series may remove the Trustee with
respect to that Series by so notifying the Trustee and the Company. The Company
may remove the Trustee with respect to Securities of one or more Series if:

                  (a)      the Trustee fails to comply with Section 7.10;

                  (b)      the Trustee is adjudged a bankrupt or an insolvent or
         an order for relief is entered with respect to the Trustee under any
         Bankruptcy Law;

                  (c)      a Custodian or public officer takes charge of the
         Trustee or its property; or

                  (d)      the Trustee becomes incapable of acting.

                  If the Trustee resigns or is removed or if a vacancy exists in
the office of Trustee for any reason, the Company shall promptly appoint a
successor Trustee. Within one year after the successor Trustee takes office, the
Holders of a majority in principal amount of the then outstanding Securities may
appoint a successor Trustee to replace the successor Trustee appointed by the
Company.

                  If a successor Trustee with respect to the Securities of any
one or more Series does not take office within 60 days after the retiring
Trustee resigns or is removed, the retiring Trustee, the Company or the Holders
of at least 10% in principal amount of the Securities of the applicable Series
may petition any court of competent jurisdiction for the appointment of a
successor Trustee.

                                       30

<PAGE>

                  If the Trustee with respect to the Securities of any one or
more Series fails to comply with Section 7.10, any Securityholder of the
applicable Series may petition any court of competent jurisdiction for the
removal of the Trustee and the appointment of a successor Trustee.

                  A successor Trustee shall deliver a written acceptance of its
appointment to the retiring Trustee and to the Company. Immediately after that,
the retiring Trustee shall transfer all property held by it as Trustee to the
successor Trustee subject to the lien provided for in Section 7.7, the
resignation or removal of the retiring Trustee shall become effective, and the
successor Trustee shall have all the rights, powers and duties of the Trustee
with respect to each Series of Securities for which it is acting as Trustee
under this Indenture. A successor Trustee shall mail a notice of its succession
to each Securityholder of each such Series and, if any Bearer Securities are
outstanding, publish such notice on one occasion in an Authorized Newspaper.
Notwithstanding replacement of the Trustee pursuant to this Section 7.8, the
Company's obligations under Section 7.7 hereof shall continue for the benefit of
the retiring trustee with respect to expenses and liabilities incurred by it
prior to such replacement.

         Section 7.9.      Successor Trustee by Merger, etc.

                  If the Trustee consolidates with, merges or converts into, or
transfers all or substantially all of its corporate trust business to, another
corporation, the successor corporation without any further act shall be the
successor Trustee.

         Section 7.10.     Eligibility; Disqualification.

                  This Indenture shall always have a Trustee who satisfies the
requirements of TIA Section 310(a)(1), (2) and (5). The Trustee shall always
have a combined capital and surplus of at least $25,000,000 as set forth in its
most recent published annual report of condition. The Trustee shall comply with
TIA Section 310(b).

         Section 7.11.     Preferential Collection of Claims Against Company.

                  The Trustee is subject to TIA Section 311(a), excluding any
creditor relationship listed in TIA Section 311(b). A Trustee who has resigned
or been removed shall be subject to TIA Section 311(a) to the extent indicated.

                                  ARTICLE VIII.
                     SATISFACTION AND DISCHARGE; DEFEASANCE

         Section 8.1.      Satisfaction and Discharge of Indenture.

                  This Indenture shall upon Company Order cease to be of further
effect (except as hereinafter provided in this Section 8.1), and the Trustee, at
the expense of the Company, shall execute proper instruments acknowledging
satisfaction and discharge of this Indenture, when

                  (a)      either

                                       31

<PAGE>

                           (i)      all Securities theretofore authenticated and
                  delivered (other than Securities that have been destroyed,
                  lost or stolen and that have been replaced or paid) have been
                  delivered to the Trustee for cancellation; or

                           (ii)     all such Securities not theretofore
                  delivered to the Trustee for cancellation

                                    (1)      have become due and payable, or

                                    (2)      will become due and payable at
                           their Stated Maturity within one year, or

                                    (3)      are to be called for redemption
                           within one year under arrangements satisfactory to
                           the Trustee for the giving of notice of redemption by
                           the Trustee in the name, and at the expense, of the
                           Company, or

                                    (4)      are deemed paid and discharged
                           pursuant to Section 8.3, as applicable;

and the Company, in the case of (1), (2) or (3) above, has deposited or caused
to be deposited with the Trustee as trust funds in trust an amount sufficient
for the purpose of paying and discharging the entire indebtedness on such
Securities not theretofore delivered to the Trustee for cancellation, for
principal and interest to the date of such deposit (in the case of Securities
which have become due and payable on or prior to the date of such deposit) or to
the Stated Maturity or redemption date, as the case may be;

                  (b)      the Company has paid or caused to be paid all other
         sums payable hereunder by the Company; and

                  (c)      the Company has delivered to the Trustee an Officers'
         Certificate and an Opinion of Counsel, each stating that all conditions
         precedent herein provided for relating to the satisfaction and
         discharge of this Indenture have been complied with.

                  Notwithstanding the satisfaction and discharge of this
Indenture, the obligations of the Company to the Trustee under Section 7.7, and,
if money shall have been deposited with the Trustee pursuant to clause (a) of
this Section, the provisions of Sections 2.4, 2.7, 2.8, 8.1 8.2 and 8.5 shall
survive.

         Section 8.2.      Application of Trust Funds; Indemnification.

                  (a)      Subject to the provisions of Section 8.5, all money
         deposited with the Trustee pursuant to Section 8.1, all money and U.S.
         Government Obligations or Foreign Government Obligations deposited with
         the Trustee pursuant to Section 8.3 or 8.4 and all money received by
         the Trustee in respect of U.S. Government Obligations or Foreign
         Government Obligations deposited with the Trustee pursuant to Section
         8.3 or 8.4, shall be held in trust and applied by it, in accordance
         with the provisions of the Securities and this Indenture, to the
         payment, either directly or through any Paying Agent (including the

                                       32

<PAGE>

         Company acting as its own Paying Agent) as the Trustee may determine,
         to the persons entitled thereto, of the principal and interest for
         whose payment such money has been deposited with or received by the
         Trustee or to make mandatory sinking fund payments or analogous
         payments as contemplated by Sections 8.3 or 8.4.

                  (b)      The Company shall pay and shall indemnify the Trustee
         against any tax, fee or other charge imposed on or assessed against
         U.S. Government Obligations or Foreign Government Obligations deposited
         pursuant to Sections 8.3 or 8.4 or the interest and principal received
         in respect of such obligations other than any payable by or on behalf
         of Holders.

                  (c)      The Trustee shall deliver or pay to the Company from
         time to time upon Company Request any U.S. Government Obligations or
         Foreign Government Obligations or money held by it as provided in
         Sections 8.3 or 8.4 which, in the opinion of a nationally recognized
         firm of independent certified public accountants expressed in a written
         certification thereof delivered to the Trustee, are then in excess of
         the amount thereof which then would have been required to be deposited
         for the purpose for which such U.S. Government Obligations or Foreign
         Government Obligations or money were deposited or received. This
         provision shall not authorize the sale by the Trustee of any U.S.
         Government Obligations or Foreign Government Obligations held under
         this Indenture.

         Section 8.3.      Legal Defeasance of Securities of any Series.

                  Unless this Section 8.3 is otherwise specified, pursuant to
Section 2.2.21, to be inapplicable to Securities of any Series, the Company
shall be deemed to have paid and discharged the entire indebtedness on all the
outstanding Securities of such Series on the 91st day after the date of the
deposit referred to in subparagraph (d) hereof, and the provisions of this
Indenture, as it relates to such outstanding Securities of such Series, shall no
longer be in effect (and the Trustee, at the expense of the Company, shall, at
Company Request, execute proper instruments acknowledging the same), except as
to:

                  (a)      the rights of Holders of Securities of such Series to
         receive, from the trust funds described in subparagraph (d) hereof, (i)
         payment of the principal of and each installment of principal of and
         interest on the outstanding Securities of such Series on the Stated
         Maturity of such principal or installment of principal or interest and
         (ii) the benefit of any mandatory sinking fund payments applicable to
         the Securities of such Series on the day on which such payments are due
         and payable in accordance with the terms of this Indenture and the
         Securities of such Series;

                  (b)      the provisions of Sections 2.4, 2.7, 2.8, 8.2, 8.3
         and 8.5; and

                  (c)      the rights, powers, trust and immunities of the
         Trustee hereunder;

provided that, the following conditions shall have been satisfied:

                  (d)      the Company shall have deposited or caused to be
         deposited irrevocably with the Trustee as trust funds in trust for the
         purpose of making the following payments,

                                       33

<PAGE>

         specifically pledged as security for and dedicated solely to the
         benefit of the Holders of such Securities (i) in the case of Securities
         of such Series denominated in Dollars, cash in Dollars (or such other
         money or currencies as shall then be legal tender in the United States)
         and/or U.S. Government Obligations, or (ii) in the case of Securities
         of such Series denominated in a Foreign Currency (other than a
         composite currency), money and/or Foreign Government Obligations, which
         through the payment of interest and principal in respect thereof, in
         accordance with their terms, will provide (and without reinvestment and
         assuming no tax liability will be imposed on such Trustee), not later
         than one day before the due date of any payment of money, an amount in
         cash, sufficient, in the opinion of a nationally recognized firm of
         independent public accountants expressed in a written certification
         thereof delivered to the Trustee, to pay and discharge each installment
         of principal (including mandatory sinking fund or analogous payments)
         of and interest, if any, on all the Securities of such Series on the
         dates such installments of interest or principal are due;

                  (e)      such deposit will not result in a breach or violation
         of, or constitute a default under, this Indenture or any other
         agreement or instrument to which the Company is a party or by which it
         is bound;

                  (f)      no Default or Event of Default with respect to the
         Securities of such Series shall have occurred and be continuing on the
         date of such deposit or during the period ending on the 91st day after
         such date;

                  (g)      the Company shall have delivered to the Trustee an
         Officers' Certificate and an Opinion of Counsel to the effect that (i)
         the Company has received from, or there has been published by, the
         Internal Revenue Service a ruling, or (ii) since the date of execution
         of this Indenture, there has been a change in the applicable Federal
         income tax law, in either case to the effect that, and based thereon
         such Opinion of Counsel shall confirm that, the Holders of the
         Securities of such Series will not recognize income, gain or loss for
         Federal income tax purposes as a result of such deposit, defeasance and
         discharge and will be subject to Federal income tax on the same amount
         and in the same manner and at the same times as would have been the
         case if such deposit, defeasance and discharge had not occurred;

                  (h)      the Company shall have delivered to the Trustee an
         Officers' Certificate stating that the deposit was not made by the
         Company with the intent of preferring the Holders of the Securities of
         such Series over any other creditors of the company or with the intent
         of defeating, hindering, delaying or defrauding any other creditors of
         the Company;

                  (i)      such deposit shall not result in the trust arising
         from such deposit constituting an investment company (as defined in the
         Investment Company Act of 1940, as amended), or such trust shall be
         qualified under such Act or exempt from regulation thereunder; and

                                       34

<PAGE>

                  (j)      the Company shall have delivered to the Trustee an
         Officers' Certificate and an Opinion of Counsel, each stating that all
         conditions precedent provided for relating to the defeasance
         contemplated by this Section have been complied with.

         Section 8.4.      Covenant Defeasance.

                  Unless this Section 8.4 is otherwise specified pursuant to
Section 2.2.21 to be inapplicable to Securities of any Series, on and after the
91st day after the date of the deposit referred to in subparagraph (a) hereof,
the Company may omit to comply with any term, provision or condition set forth
under Sections 4.2, 4.3, 4.4, 4.5, 4.6, and 5.1 as well as any additional
covenants contained in a supplemental indenture hereto for a particular Series
of Securities or a Board Resolution or an Officers' Certificate delivered
pursuant to Section 2.2.21 (and the failure to comply with any such covenants
shall not constitute a Default or Event of Default under Section 6.1) and the
occurrence of any event described in clause (e) of Section 6.1 shall not
constitute a Default or Event of Default hereunder, with respect to the
Securities of such Series, provided that the following conditions shall have
been satisfied:

                  (a)      With reference to this Section 8.4, the Company has
         deposited or caused to be irrevocably deposited (except as provided in
         Section 8.2(c)) with the Trustee as trust funds in trust, specifically
         pledged as security for, and dedicated solely to, the benefit of the
         Holders of such Securities (i) in the case of Securities of such Series
         denominated in Dollars, cash in Dollars (or such other money or
         currencies as shall then be legal tender in the United States) and/or
         U.S. Government Obligations, or (ii) in the case of Securities of such
         Series denominated in a Foreign Currency (other than a composite
         currency), money and/or Foreign Government Obligations, which through
         the payment of interest and principal in respect thereof, in accordance
         with their terms, will provide (and without reinvestment and assuming
         no tax liability will be imposed on such Trustee), not later than one
         day before the due date of any payment of money, an amount in cash,
         sufficient, in the opinion of a nationally recognized firm of
         independent certified public accountants expressed in a written
         certification thereof delivered to the Trustee, to pay principal and
         interest, if any, on and any mandatory sinking fund in respect of the
         Securities of such Series on the dates such installments of interest or
         principal are due;

                  (b)      Such deposit will not result in a breach or violation
         of, or constitute a default under, this Indenture or any other
         agreement or instrument to which the Company is a party or by which it
         is bound;

                  (c)      No Default or Event of Default with respect to the
         Securities of such Series shall have occurred and be continuing on the
         date of such deposit or during the period ending on the 91st day after
         such date;

                  (d)      the Company shall have delivered to the Trustee an
         Opinion of Counsel confirming that Holders of the Securities of such
         Series will not recognize income, gain or loss for federal income tax
         purposes as a result of such deposit and defeasance and will be subject
         to federal income tax on the same amounts, in the same manner and at
         the same times as would have been the case if such deposit and
         defeasance had not occurred;

                                       35

<PAGE>

                  (e)      the Company shall have delivered to the Trustee an
         Officers' Certificate stating the deposit was not made by the Company
         with the intent of preferring the Holders of the Securities of such
         Series over any other creditors of the Company or with the intent of
         defeating, hindering, delaying or defrauding any other creditors of the
         Company; and

                  (f)      The Company shall have delivered to the Trustee an
         Officers' Certificate and an Opinion of Counsel, each stating that all
         conditions precedent herein provided for relating to the defeasance
         contemplated by this Section have been complied with.

         Section 8.5.      Repayment to Company.

                  The Trustee and the Paying Agent shall pay to the Company upon
request any money held by them for the payment of principal and interest that
remains unclaimed for two years. After that, Securityholders entitled to the
money must look to the Company for payment as general creditors unless an
applicable abandoned property law designates another person.

         Section 8.6.      Reinstatement.

                  If the Trustee or Paying Agent is unable to apply any money or
U.S. Government Obligations in accordance with Sections 8.1, 8.3 or 8.4, as the
case may be, by reason of any legal proceeding or by reason of any order or
judgment of any court or governmental authority enjoining, restraining or
otherwise prohibiting such application, the Company's obligations under this
Indenture and the Securities shall be revived and reinstated as though no
deposit had occurred pursuant to Section 8.1, 8.3 or 8.4, as the case may be,
until such time as the Trustee or Paying Agent is permitted to apply all such
money or U.S. Government Obligations in accordance with Section 8.1, 8.3 or 8.4,
as the case may be; provided, however, that if the Company makes any payment of
principal of, premium, if any, or interest on any Securities because of
reinstatement of its obligations, the Company shall be subrogated to the rights
of the holders of such Securities to receive such payment from the money or U.S.
Government Obligations held by the Trustee or Paying Agent.

                                   ARTICLE IX.
                             AMENDMENTS AND WAIVERS

         Section 9.1.      Without Consent of Holders.

                  The Company and the Trustee may amend or supplement this
Indenture or the Securities of one or more Series without the consent of any
Securityholder:

                  (a)      to cure any ambiguity, defect or inconsistency;

                  (b)      to comply with Article V;

                  (c)      to provide for uncertificated Securities in addition
         to or in place of certificated Securities;

                                       36

<PAGE>

                  (d)      to make any change that does not adversely affect the
         rights of any Securityholder;

                  (e)      to provide for the issuance of and establish the form
         and terms and conditions of Securities of any Series as permitted by
         this Indenture;

                  (f)      to evidence and provide for the acceptance of
         appointment hereunder by a successor Trustee with respect to the
         Securities of one or more Series and to add to or change any of the
         provisions of this Indenture as shall be necessary to provide for or
         facilitate the administration of the trusts hereunder by more than one
         Trustee; or

                  (g)      to comply with requirements of the SEC in order to
         effect or maintain the qualification of this Indenture under the TIA.

         Section 9.2.      With Consent of Holders.

                  The Company and the Trustee may enter into a supplemental
indenture with the written consent of the Holders of at least a majority in
principal amount of the outstanding Securities of each Series affected by such
supplemental indenture (including consents obtained in connection with a tender
offer or exchange offer for the Securities of such Series), for the purpose of
adding any provisions to or changing in any manner or eliminating any of the
provisions of this Indenture or of any supplemental indenture or of modifying in
any manner the rights of the Securityholders of each such Series. Except as
provided in Section 6.13, the Holders of at least a majority in principal amount
of the outstanding Securities of each Series affected by such waiver by notice
to the Trustee (including consents obtained in connection with a tender offer or
exchange offer for the Securities of such Series) may waive compliance by the
Company with any provision of this Indenture or the Securities with respect to
such Series.

                  It shall not be necessary for the consent of the Holders of
Securities under this Section 9.2 to approve the particular form of any proposed
supplemental indenture or waiver, but it shall be sufficient if such consent
approves the substance thereof. After a supplemental indenture or waiver under
this section becomes effective, the Company shall mail to the Holders of
Securities affected thereby and, if any Bearer Securities affected thereby are
outstanding, publish on one occasion in an Authorized Newspaper, a notice
briefly describing the supplemental indenture or waiver. Any failure by the
Company to mail or publish such notice, or any defect therein, shall not,
however, in any way impair or affect the validity of any such supplemental
indenture or waiver.

         Section 9.3.      Limitations.

                  Without the consent of each Securityholder affected, an
amendment or waiver may not:

                  (a)      change the amount of Securities whose Holders must
         consent to an amendment, supplement or waiver;

                  (b)      reduce the rate of or extend the time for payment of
         interest (including default interest) on any Security;

                                       37

<PAGE>

                  (c)      reduce the principal or change the Stated Maturity of
         any Security or reduce the amount of, or postpone the date fixed for,
         the payment of any sinking fund or analogous obligation;

                  (d)      reduce the principal amount of Discount Securities
         payable upon acceleration of the maturity thereof;

                  (e)      waive a Default or Event of Default in the payment of
         the principal of or interest, if any, on any Security (except a
         rescission of acceleration of the Securities of any Series by the
         Holders of at least a majority in principal amount of the outstanding
         Securities of such Series and a waiver of the payment default that
         resulted from such acceleration);

                  (f)      make the principal of or interest, if any, on any
         Security payable in any currency other than that stated in the
         Security;

                  (g)      make any change in Sections 6.8, 6.13, 9.3 (this
         sentence), 10.15 or 10.16; or

                  (h)      waive a redemption payment with respect to any
         Security or change any of the provisions with respect to the redemption
         of any Securities.

         Section 9.4.      Compliance with Trust Indenture Act.

                  Every amendment to this Indenture or the Securities of one or
more Series shall be set forth in a supplemental indenture hereto that complies
with the TIA as then in effect.

         Section 9.5.      Revocation and Effect of Consents.

                  Until an amendment or waiver becomes effective, a consent to
it by a Holder of a Security is a continuing consent by the Holder and every
subsequent Holder of a Security or portion of a Security that evidences the same
debt as the consenting Holder's Security, even if notation of the consent is not
made on any Security. However, any such Holder or subsequent Holder may revoke
the consent as to his Security or portion of a Security if the Trustee receives
the notice of revocation before the date the amendment or waiver becomes
effective.

                  Any amendment or waiver once effective shall bind every
Securityholder of each Series affected by such amendment or waiver unless it is
of the type described in any of clauses (a) through (g) of Section 9.3. In that
case, the amendment or waiver shall bind each Holder of a Security who has
consented to it and every subsequent Holder of a Security or portion of a
Security that evidences the same debt as the consenting Holder's Security.

         Section 9.6.      Notation on or Exchange of Securities.

                  The Trustee may place an appropriate notation about an
amendment or waiver on any Security of any Series thereafter authenticated. The
Company in exchange for Securities of that Series may issue and the Trustee
shall authenticate upon request new Securities of that Series that reflect the
amendment or waiver.

                                       38

<PAGE>

         Section 9.7.      Trustee Protected.

                  In executing, or accepting the additional trusts created by,
any supplemental indenture permitted by this Article or the modifications
thereby of the trusts created by this Indenture, the Trustee shall be entitled
to receive, and (subject to Section 7.1) shall be fully protected in relying
upon, an Opinion of Counsel stating that the execution of such supplemental
indenture is authorized or permitted by this Indenture. The Trustee shall sign
all supplemental indentures, except that the Trustee need not sign any
supplemental indenture that adversely affects its rights.

                                   ARTICLE X.
                                  MISCELLANEOUS

         Section 10.1.     Trust Indenture Act Controls.

                  If any provision of this Indenture limits, qualifies, or
conflicts with another provision which is required or deemed to be included in
this Indenture by the TIA, such required or deemed provision shall control.

         Section 10.2.     Notices.

                  Any notice or communication by the Company or the Trustee to
the other is duly given if in writing and delivered in person or mailed by
first-class mail:

if to the Company:

                  Nuvelo, Inc.
                  675 Almanor Avenue
                  Sunnyvale, CA 94085
                  Attention: General Counsel

if to the Trustee:

                  [Name of Trustee]
                  [Address]
                  _________________________
                  _________________________
                  Attention: ______________

                  The Company or the Trustee by notice to the other may
designate additional or different addresses for subsequent notices or
communications.

                  Any notice or communication to a Securityholder shall be
mailed by first-class mail to his address shown on the register kept by the
Registrar and, if any Bearer Securities are outstanding, published in an
Authorized Newspaper. Failure to mail a notice or communication to a
Securityholder of any Series or any defect in it shall not affect its
sufficiency with respect to other Securityholders of that or any other Series.

                                       39

<PAGE>

                  If a notice or communication is mailed or published in the
manner provided above, within the time prescribed, it is duly given, whether or
not the Securityholder receives it.

                  If the Company mails a notice or communication to
Securityholders, it shall mail a copy to the Trustee and each Agent at the same
time.

         Section 10.3.     Communication by Holders with Other Holders.

                  Securityholders of any Series may communicate pursuant to TIA
Section 312(b) with other Securityholders of that Series or any other Series
with respect to their rights under this Indenture or the Securities of that
Series or all Series. The Company, the Trustee, the Registrar and anyone else
shall have the protection of TIA Section 312(c).

         Section 10.4.     Certificate and Opinion as to Conditions Precedent.

                  Upon any request or application by the Company to the Trustee
to take any action under this Indenture, the Company shall furnish to the
Trustee:

                  (a)      an Officers' Certificate stating that, in the opinion
         of the signers, all conditions precedent, if any, provided for in this
         Indenture relating to the proposed action have been complied with; and

                  (b)      an Opinion of Counsel stating that, in the opinion of
         such counsel, all such conditions precedent have been complied with.

         Section 10.5.     Statements Required in Certificate or Opinion.

                  Each certificate or opinion with respect to compliance with a
condition or covenant provided for in this Indenture (other than a certificate
provided pursuant to TIA Section 314(a)(4)) shall comply with the provisions of
TIA Section 314(e) and shall include:

                  (a)      a statement that the person making such certificate
         or opinion has read such covenant or condition;

                  (b)      a brief statement as to the nature and scope of the
         examination or investigation upon which the statements or opinions
         contained in such certificate or opinion are based;

                  (c)      a statement that, in the opinion of such person, he
         has made such examination or investigation as is necessary to enable
         him to express an informed opinion as to whether or not such covenant
         or condition has been complied with; and

                  (d)      a statement as to whether or not, in the opinion of
         such person, such condition or covenant has been complied with.

         Section 10.6.     Rules by Trustee and Agents.

                                       40

<PAGE>

                  The Trustee may make reasonable rules for action by or a
meeting of Securityholders of one or more Series. Any Agent may make reasonable
rules and set reasonable requirements for its functions.

         Section 10.7.     Legal Holidays.

                  Unless otherwise provided by Board Resolution, Officers'
Certificate or supplemental indenture for a particular Series, a "Legal Holiday"
is any day that is not a Business Day. If a payment date is a Legal Holiday at a
place of payment, payment may be made at that place on the next succeeding day
that is not a Legal Holiday, and no interest shall accrue for the intervening
period.

         Section 10.8.     No Recourse Against Others.

                  A director, officer, employee or stockholder, as such, of the
Company shall not have any liability for any obligations of the Company under
the Securities or the Indenture or for any claim based on, in respect of or by
reason of such obligations or their creation. Each Securityholder by accepting a
Security waives and releases all such liability. The waiver and release are part
of the consideration for the issue of the Securities.

         Section 10.9.     Counterparts.

                  This Indenture may be executed in any number of counterparts
and by the parties hereto in separate counterparts, each of which when so
executed shall be deemed to be an original and all of which taken together shall
constitute one and the same agreement.

         Section 10.10.    Governing Laws.

                  THIS INDENTURE AND THE SECURITIES SHALL BE GOVERNED BY THE
LAWS OF THE STATE OF NEW YORK APPLICABLE TO AGREEMENTS MADE AND TO BE PERFORMED
IN SUCH STATE, WITHOUT REGARD TO THE CONFLICT OF LAWS PROVISIONS THEREOF.

         Section 10.11.    No Adverse Interpretation of Other Agreements.

                  This Indenture may not be used to interpret another indenture,
loan or debt agreement of the Company or a Subsidiary. Any such indenture, loan
or debt agreement may not be used to interpret this Indenture.

         Section 10.12.    Successors.

                  All agreements of the Company in this Indenture and the
Securities shall bind its successor. All agreements of the Trustee in this
Indenture shall bind its successor.

                                       41

<PAGE>

         Section 10.13.    Severability.

                  In case any provision in this Indenture or in the Securities
shall be invalid, illegal or unenforceable, the validity, legality and
enforceability of the remaining provisions shall not in any way be affected or
impaired thereby.

         Section 10.14.    Table of Contents, Headings, Etc.

                  The Table of Contents, Cross Reference Table, and headings of
the Articles and Sections of this Indenture have been inserted for convenience
of reference only, are not to be considered a part hereof, and shall in no way
modify or restrict any of the terms or provisions hereof.

         Section 10.15.    Securities in a Foreign Currency or in ECU.

                  Unless otherwise specified in a Board Resolution, a
supplemental indenture hereto or an Officers' Certificate delivered pursuant to
Section 2.2 of this Indenture with respect to a particular Series of Securities,
whenever for purposes of this Indenture any action may be taken by the Holders
of a specified percentage in aggregate principal amount of Securities of all
Series or all Series affected by a particular action at the time outstanding
and, at such time, there are outstanding Securities of any Series which are
denominated in a coin or currency other than Dollars (including ECUs), then the
principal amount of Securities of such Series which shall be deemed to be
outstanding for the purpose of taking such action shall be that amount of
Dollars that could be obtained for such amount at the Market Exchange Rate at
such time. For purposes of this Section 10.15, "Market Exchange Rate" shall mean
the noon Dollar buying rate in New York City for cable transfers of that
currency as published by the Federal Reserve Bank of New York; provided,
however, in the case of ECUs, Market Exchange Rate shall mean the rate of
exchange determined by the Commission of the European Union (or any successor
thereto) as published in the Official Journal of the European Union (such
publication or any successor publication, the "Journal"). If such Market
Exchange Rate is not available for any reason with respect to such currency, the
Trustee shall use, in its sole discretion and without liability on its part,
such quotation of the Federal Reserve Bank of New York or, in the case of ECUs,
the rate of exchange as published in the Journal, as of the most recent
available date, or quotations or, in the case of ECUs, rates of exchange from
one or more major banks in The City of New York or in the country of issue of
the currency in question or, in the case of ECUs, in Luxembourg or such other
quotations or, in the case of ECUs, rates of exchange as the Trustee, upon
consultation with the Company, shall deem appropriate. The provisions of this
paragraph shall apply in determining the equivalent principal amount in respect
of Securities of a Series denominated in currency other than Dollars in
connection with any action taken by Holders of Securities pursuant to the terms
of this Indenture.

                  All decisions and determinations of the Trustee regarding the
Market Exchange Rate or any alternative determination provided for in the
preceding paragraph shall be in its sole discretion and shall, in the absence of
manifest error, be conclusive to the extent permitted by law for all purposes
and irrevocably binding upon the Company and all Holders.

                                       42

<PAGE>

         Section 10.16.    Judgment Currency.

                  The Company agrees, to the fullest extent that it may
effectively do so under applicable law, that (a) if for the purpose of obtaining
judgment in any court it is necessary to convert the sum due in respect of the
principal of or interest or other amount on the Securities of any Series (the
"Required Currency") into a currency in which a judgment will be rendered (the
"Judgment Currency"), the rate of exchange used shall be the rate at which in
accordance with normal banking procedures the Trustee could purchase in The City
of New York the Required Currency with the Judgment Currency on the day on which
final unappealable judgment is entered, unless such day is not a New York
Banking Day, then, the rate of exchange used shall be the rate at which in
accordance with normal banking procedures the Trustee could purchase in The City
of New York the Required Currency with the Judgment Currency on the New York
Banking Day preceding the day on which final unappealable judgment is entered
and (b) its obligations under this Indenture to make payments in the Required
Currency (i) shall not be discharged or satisfied by any tender, any recovery
pursuant to any judgment (whether or not entered in accordance with subsection
(a)), in any currency other than the Required Currency, except to the extent
that such tender or recovery shall result in the actual receipt, by the payee,
of the full amount of the Required Currency expressed to be payable in respect
of such payments, (ii) shall be enforceable as an alternative or additional
cause of action for the purpose of recovering in the Required Currency the
amount, if any, by which such actual receipt shall fall short of the full amount
of the Required Currency so expressed to be payable, and (iii) shall not be
affected by judgment being obtained for any other sum due under this Indenture.
For purposes of the foregoing, "New York Banking Day" means any day except a
Saturday, Sunday or a legal holiday in The City of New York on which banking
institutions are authorized or required by law, regulation or executive order to
close.

                                   ARTICLE XI.
                                  SINKING FUNDS

         Section 11.1.     Applicability of Article.

                  The provisions of this Article shall be applicable to any
sinking fund for the retirement of the Securities of a Series, except as
otherwise permitted or required by any form of Security of such Series issued
pursuant to this Indenture.

                  The minimum amount of any sinking fund payment provided for by
the terms of the Securities of any Series is herein referred to as a "mandatory
sinking fund payment" and any other amount provided for by the terms of
Securities of such Series is herein referred to as an "optional sinking fund
payment." If provided for by the terms of Securities of any Series, the cash
amount of any sinking fund payment may be subject to reduction as provided in
Section 11.2. Each sinking fund payment shall be applied to the redemption of
Securities of any Series as provided for by the terms of the Securities of such
Series.

         Section 11.2.     Satisfaction of Sinking Fund Payments with
Securities.

                  The Company may, in satisfaction of all or any part of any
sinking fund payment with respect to the Securities of any Series to be made
pursuant to the terms of such Securities

                                       43

<PAGE>

(1) deliver outstanding Securities of such Series to which such sinking fund
payment is applicable (other than any of such Securities previously called for
mandatory sinking fund redemption) and (2) apply as credit Securities of such
Series to which such sinking fund payment is applicable and which have been
redeemed either at the election of the Company pursuant to the terms of such
Series of Securities (except pursuant to any mandatory sinking fund) or through
the application of permitted optional sinking fund payments or other optional
redemptions pursuant to the terms of such Securities, provided that such
Securities have not been previously so credited. Such Securities shall be
received by the Trustee, together with an Officers' Certificate with respect
thereto, not later than 15 days prior to the date on which the Trustee begins
the process of selecting Securities for redemption, and shall be credited for
such purpose by the Trustee at the price specified in such Securities for
redemption through operation of the sinking fund and the amount of such sinking
fund payment shall be reduced accordingly. If as a result of the delivery or
credit of Securities in lieu of cash payments pursuant to this Section 11.2, the
principal amount of Securities of such Series to be redeemed in order to exhaust
the aforesaid cash payment shall be less than $100,000, the Trustee need not
call Securities of such Series for redemption, except upon receipt of a Company
Order that such action be taken, and such cash payment shall be held by the
Trustee or a Paying Agent and applied to the next succeeding sinking fund
payment, provided, however, that the Trustee or such Paying Agent shall from
time to time upon receipt of a Company Order pay over and deliver to the Company
any cash payment so being held by the Trustee or such Paying Agent upon delivery
by the Company to the Trustee of Securities of that Series purchased by the
Company having an unpaid principal amount equal to the cash payment required to
be released to the Company.

         Section 11.3.     Redemption of Securities for Sinking Fund.

                  Not less than 45 days (unless otherwise indicated in the Board
Resolution, supplemental indenture hereto or Officers' Certificate in respect of
a particular Series of Securities) prior to each sinking fund payment date for
any Series of Securities, the Company will deliver to the Trustee an Officers'
Certificate specifying the amount of the next ensuing mandatory sinking fund
payment for that Series pursuant to the terms of that Series, the portion
thereof, if any, which is to be satisfied by payment of cash and the portion
thereof, if any, which is to be satisfied by delivering and crediting of
Securities of that Series pursuant to Section 11.2, and the optional amount, if
any, to be added in cash to the next ensuing mandatory sinking fund payment, and
the Company shall thereupon be obligated to pay the amount therein specified.
Not less than 30 days (unless otherwise indicated in the Board Resolution,
Officers' Certificate or supplemental indenture in respect of a particular
Series of Securities) before each such sinking fund payment date the Trustee
shall select the Securities to be redeemed upon such sinking fund payment date
in the manner specified in Section 3.2 and cause notice of the redemption
thereof to be given in the name of and at the expense of the Company in the
manner provided in Section 3.3. Such notice having been duly given, the
redemption of such Securities shall be made upon the terms and in the manner
stated in Sections 3.4, 3.5 and 3.6.

                                       44

<PAGE>

                  IN WITNESS WHEREOF, the parties hereto have caused this
Indenture to be duly executed as of the day and year first above written.

                                      NUVELO, INC.

                                      By: ______________________________________
                                          Name:
                                          Its:

                                      [Name of Trustee]

                                      By: ______________________________________
                                          Name:
                                          Its: