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                                                                    EXHIBIT 10.6

                              AMENDED AND RESTATED
                         EXECUTIVE EMPLOYMENT AGREEMENT

     This Amended and Restated Executive Employment Agreement ("Agreement") is
effective as of January 1, 2005 ("Effective Date"), by and between Structural
GenomiX, Inc., with its principal place of business at 10505 Roselle Street, San
Diego, California 92121 ("SGX"), a Delaware corporation, and Michael Grey, who
resides at ___________________________________________________ ("Executive").
This Agreement amends and restates and supercedes and terminates in its entirety
that certain Employment Agreement dated September 4, 2001 by and between SGX and
Executive, as amended by that certain letter agreement dated December 20, 2004
(together, the "Prior Agreement").

     The parties agree as follows:

     1. Employment. SGX hereby employs Executive, and Executive hereby accepts
such employment, upon the terms and conditions set forth herein.

     2. Duties.

          2.1. Position; Duties and Responsibilities. Executive is employed in
the position of President and Chief Executive Officer and shall have the duties
and responsibilities assigned by the Board of Directors of SGX (the "Board").
Executive is responsible for overseeing the business and operations of SGX and
doing and performing all services, acts, or things reasonably necessary or
advisable to accomplish the objectives and complete the tasks assigned to
Executive by the Board. Executive shall serve as the leader and principal
officer of the executive team and shall report directly to the Board. Executive
shall perform faithfully and diligently such duties, as well as such other
duties as the Board shall reasonably assign from time to time. SGX reserves the
right to modify Executive's position and duties at any time in its sole and
reasonable discretion.

          2.2. Best Efforts/Full-time. Executive will expend Executive's best
efforts on behalf of SGX, and will abide by all policies and decisions made by
SGX, as well as all applicable federal, state and local laws, regulations or
ordinances. Executive will act in the best interest of SGX at all times.
Executive shall devote Executive's full business time and efforts to the
performance of Executive's assigned duties, unless Executive notifies SGX in
advance of Executive's intent to engage in other paid work and receives SGX'
express written consent to do so. SGX consents to the continuing service by
Executive on the Boards of Directors of Achillion Pharmaceuticals, Inc. and
Epimmune, Inc. Executive must not engage in any work, paid or unpaid, that
creates an actual or potential conflict of interest with SGX. If SGX believes a
conflict exists, SGX may ask Executive to choose whether to discontinue the
other work or resign employment with SGX.

          2.3. Board Seat. Executive shall continue to serve as a member of the
Board.

          2.4. Work Location. Executive's principal place of work shall be
located in San Diego, California, at SGX' offices or as reasonably assigned by
SGX.

     3. Term. The employment relationship pursuant to this Agreement shall be
for an initial term commencing on the Effective Date set forth above and
continuing for the period of one (1) year and for consecutive one year terms
thereafter unless sooner terminated in accordance with paragraph 7 below.

     4. Compensation.

          4.1. Salary. As compensation for the proper and satisfactory
performance of all duties to be performed by Executive hereunder, SGX shall pay
to Executive an initial annualized Base Salary of Three Hundred Fifty Thousand
($350,000) per year, payable in accordance with the normal payroll practices of
SGX, less required deductions for state and federal withholding tax, social
security and all other employment taxes and payroll deductions. In the event
Executive's employment under this Agreement is terminated by either party, for
any reason, Executive will be entitled to receive the Base Salary prorated to
the date of termination.

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          4.2. Incentive Compensation. Executive will be eligible to receive
incentive compensation. If SGX, in its sole and absolute discretion, grants
executive incentive compensation, the terms, amount and payment of such, if any,
will be determined solely by SGX.

          4.3. Stock Options. Executive will receive a stock option or stock
options to purchase that number of shares of SGX common stock that, together
with Executive's currently outstanding stock options, if any, is equal to 3.5%
of the Fully Diluted Capitalization (as defined below) of SGX after giving
effect to the Next Equity Financing (as defined below), at a price per share
equal to the fair market value of SGX' common stock on the date of grant of each
such stock option as shall be determined by the Board in its sole and absolute
discretion. 25% of the shares subject to such stock options shall be fully
vested as of the date of grant and the remaining shares subject to such stock
options shall vest over three years after the vesting commencement date in equal
monthly installments (subject to acceleration of vesting under certain
circumstances as set forth in subparagraphs 7.2 and 7.4(a) below). Such stock
options shall be subject to the terms and conditions of SGX' 2000 Equity
Incentive Plan (the "Incentive Plan") and SGX' form of stock option agreement.
The Board shall grant such stock options as soon as reasonably practicable after
the number of shares issuable in connection with such Next Equity Financing is
ascertainable and the vesting commencement date of all such stock options shall
be the Effective Date. The offer of such stock options is conditioned upon
Executive's acceptance of this Agreement and will be in accordance with the
terms and requirements of the Incentive Plan and SGX' form of stock option
agreement. "Fully Diluted Capitalization" as used in this subparagraph 4.3 shall
mean the fully-diluted capitalization of SGX calculated on an as-converted basis
and including all outstanding preferred stock, common stock, warrants, all
options authorized under equity incentive plans (whether or not granted or
vested), and securities issuable upon conversion of outstanding convertible
notes, if any (but excluding shares issuable upon conversion of the Millennium
convertible note). "Next Equity Financing" as used in this subparagraph 4.3
shall mean the next private equity financing of SGX primarily for capital
raising purposes that raises at least $5 million of new investment and occurs
prior to the completion of an initial public offering of SGX' securities, and
such Next Equity Financing shall include the aggregate number of shares to be
issued in connection with such financing (including, if the financing occurs in
multiple tranches, the aggregate number of shares that are issued in all
tranches for which there is a contractual commitment to fund on the part of the
investors in such Next Equity Financing as of the initial closing thereof). Any
obligation of SGX that remains outstanding under this subparagraph 4.3 to grant
any additional stock options to Executive shall terminate and be of no further
force or effect upon the earlier to occur of (i) immediately prior to the
closing of an initial public offering of SGX' securities or (ii) immediately
prior to the consummation of a Change of Control (as defined below).

          4.4. Cash Bonus Program. As Executive Vice President and Chief
Business Officer, Executive is eligible to earn a cash bonus equal to 35% of
Executive's base salary, or $122,500, provided Executive meets the eligibility
requirements and performance objectives set forth in SGX' bonus program, which
are determined in SGX' sole discretion.

          4.5. Performance and Salary Review. SGX will periodically review
Executive's performance. Executive's salary and/or other compensation will be
reviewed yearly and may be adjusted from time to time in SGX' sole and absolute
discretion.

     5. Customary Fringe Benefits. Executive will be eligible for all customary
and usual fringe benefits generally available to executives of SGX subject to
the terms and conditions of SGX' benefit plan documents. SGX reserves the right
to modify or eliminate the fringe benefits on a prospective basis, at any time,
effective upon notice to Executive.

     6. Business Expenses. Executive will be reimbursed for all out-of-pocket
business expenses reasonably incurred in the performance of Executive's duties
on behalf of SGX. To obtain reimbursement, expenses must be submitted promptly
with appropriate supporting documentation in accordance with SGX' policies.

     7. Termination of Employment.

          7.1. Termination for Cause by SGX. Although SGX anticipates a mutually
rewarding employment relationship with Executive, SGX may terminate Executive's
employment immediately at any time for cause. Cause includes, but is not limited
to, one or more of the following: (a) acts or omissions deemed by SGX to

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constitute gross negligence, recklessness, willful misconduct or dishonesty on
the part of Executive with respect to Executive's obligations under this
Agreement or otherwise relating to the business of SGX; (b) Executive's willful,
material breach of this Agreement; (c) Executive's conviction or entry of a plea
of guilty or nolo contendere for fraud, misappropriation or embezzlement, or of
any felony; (d) Executive's material breach of fiduciary duty toward SGX; (e)
Executive's material breach of any element of SGX' Confidential Information and
Invention Assignment Agreement, including without limitation, Executive's theft,
dilution, or other misappropriation or careless treatment of SGX' proprietary
information; (f) Executive's inability to perform all of the essential functions
and duties of Executive's position, with or without reasonable accommodation
other than for reason of temporary illness; or (g) Executive's death. In the
event Executive's employment is terminated in accordance with this subparagraph
7.1, Executive shall be entitled to receive only the Base Salary then in effect,
prorated to the date of termination, and any benefits, including any benefits
under the Bonus Plan and Incentive Plan, and expense reimbursements to which
Executive is entitled by virtue of his prior employment with SGX (collectively
referred to as "Standard Entitlements."). All other SGX obligations to Executive
pursuant to this Agreement will become automatically terminated and completely
extinguished. Executive will not be entitled to receive the Severance Payment or
any part thereof described in subparagraph 7.2 below.

          7.2. Termination Without Cause By SGX/Severance. SGX may terminate
Executive's employment under this Agreement without cause at any time on thirty
(30) days' advance written notice to Executive. In the event of such
termination, Executive will receive the Standard Entitlements, plus a severance
payment equivalent to twelve months of Executive's Base Salary then in effect on
the date of termination (the "Severance Payment") payable in accordance with
SGX' regular payroll cycle, and the vesting of any outstanding stock options
will be accelerated by 12 months, provided that Executive: (a) complies with all
surviving provisions of this Agreement as specified in subparagraph 16.7 below;
(b) executes a full general release, releasing all claims, known or unknown,
that Executive may have against SGX arising out of or any way related to
Executive's employment or termination of employment with SGX; and (c) agrees to
act as a consultant for SGX for up to a maximum of sixty (60) days, without
additional compensation, if requested to do so by SGX. All other SGX obligations
to Executive pursuant to this Agreement will become automatically terminated and
completely extinguished.

          7.3. Voluntary Resignation By Executive. Executive may voluntarily
resign Executive's position with SGX at any time on thirty (30) days advance
written notice. In the event of Executive's resignation, Executive shall be
entitled to receive only the Base Salary then in effect, prorated to the date of
resignation, and the Standard Entitlements. All other SGX obligations to
Executive pursuant to this Agreement will become automatically terminated and
completely extinguished. In addition, Executive will not be entitled to receive
the Severance Payment described in paragraph 7.2 above.

          7.4. Termination of Executive Following Change Of Control.

               (a) Severance Payment. If Executive's employment is terminated by
SGX without cause within one year after a Change of Control (as that term is
defined below), Executive shall be entitled to receive the Standard
Entitlements, plus the Severance Payment described in subparagraph 7.2 above,
and that the vesting of any outstanding stock options will be accelerated by 24
months, provided Executive complies with the conditions in subparagraph 7.2
above. All other SGX obligations to Executive pursuant to this Agreement will
become automatically terminated and completely extinguished.

               (b) 280G. If, due to the benefits provided under subparagraph
7.4(a) above, Executive is subject to any excise tax due to characterization of
any amounts payable under subparagraph 7.4(a) as excess parachute payments
pursuant to Section 4999 of the Internal Revenue Code of 1986, as amended (the
"Code"), Executive may elect, in Executive's sole discretion, to reduce the
amounts payable under subparagraph 7.4(a) in order to avoid any "excess
parachute payment" under Section 280G(b)(1) of the Code.

               (c) Change of Control. A Change of Control is defined as any one
of the following occurrences:

                    (i) Any "person" (as such term is used in Sections 13(d) and
14(d) of the Securities Exchange Act of 1934 (the "Exchange Act"), other than a
trustee or other fiduciary holding securities of

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SGX under an employee benefit plan of SGX, becomes the "beneficial owner" (as
defined in Rule 13d-3 promulgated under the Exchange Act), directly or
indirectly, of the securities of SGX representing more than 50% of (a) the
outstanding shares of common stock of SGX or (b) the combined voting power of
SGX' then-outstanding securities; or

                    (ii) The sale or disposition of all or substantially all of
SGX' assets (or any transaction having similar effect is consummated) other than
to an entity of which SGX owns at least 50% of the Voting Stock so long as the
sale or disposition is not under duress of SGX' financial hardship; or

                    (iii) SGX is party to a merger or consolidation that results
in the holders of voting securities of SGX outstanding immediately prior thereto
failing to continue to represent (either by remaining outstanding or by being
converted into voting securities of the surviving entity) less than 50% of the
combined voting power of the voting securities of SGX or such surviving entity
outstanding immediately after such merger or consolidation.

     8. Competitive Employment. During the term of Executive's employment with
SGX and during any period in which Executive is receiving payments (other than
any dividends on stock) from SGX or acting as a consultant with or without
payment, Executive agrees that Executive will not directly or indirectly compete
with SGX in any way, and will not act as an officer, director, executive,
consultant, shareholder (other than stock of publicly held companies),
volunteer, lender, or agent of any business enterprise of the same nature as, or
which is in competition with, the business in which SGX is now engaged or in
which SGX becomes engaged during the term of Executive's employment with SGX, as
may be determined by SGX in its sole discretion. Further, Executive agrees not
to refer any client or potential client to competitors of SGX without SGX'
written consent during the term of Executive's employment with SGX or during any
period in which Executive is receiving payments (other than any dividends on
stock) from SGX or acting as a consultant with or without payment.

     9. Confidentiality and Proprietary Rights. Executive agrees to abide by
SGX' proprietary rights policies and to protect the intellectual property of
SGX. In accordance, Executive has signed, contemporaneously with the execution
of this Agreement, a Confidential Information and Invention Assignment
Agreement, which is incorporated herein by this reference.

     10. Non-Solicitation.

          10.1. Non-Solicitation of Employees and Independent Contractors.
Executive agrees that during Executive's employment with SGX and for a period of
one year after the termination of Executive's employment with SGX, Executive
will not directly or indirectly, separately or in association with others,
interfere with, impair, disrupt or damage SGX' relationship with any employee or
independent contractor; solicit, encourage or attempt to hire any of SGX'
employees or independent contractors; or cause others to solicit or encourage
any of SGX' employees or independent contractors to discontinue their employment
or services with SGX.

          10.2. Non-Solicitation of Customers. Executive acknowledges that
proprietary information about SGX' customers is confidential and constitutes
trade secrets of SGX. Executive agrees that during Executive's employment with
SGX and for a period of one year following the termination of Executive's
employment with SGX, Executive will not, either directly or indirectly,
separately or in association with others, do any of the following: (i) make
known, to any person, firm or corporation, the names and addresses of any of the
customers of SGX or contacts of SGX within the pharmaceutical or biotechnology
industry or any other information pertaining to such persons; (ii) call on,
solicit, take away, or attempt to call on, solicit or take away any of the
customers of SGX on whom Executive called or with whom Executive became aware or
acquainted during Executive's association with SGX, whether for Executive or for
any other person, firm or corporation; or (iii) use or make known to any person
or entity, the strategies, tactics, practices, and procedures by which SGX does
business.

     11. Injunctive Relief. Executive acknowledges that Executive's breach of
the covenants contained in paragraphs 8-10 (collectively "Covenants") would
cause irreparable injury to SGX and agrees that in the event of any such breach,
SGX shall be entitled to seek temporary, preliminary and permanent injunctive
relief without the necessity of proving actual damages or posting any bond or
other security.

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     12. Accounting and Indemnification. In the event Executive breaches any of
the Covenants contained in paragraphs 8-10, SGX shall have the right and remedy
to require Executive to: (a) account for and pay over to SGX all compensation,
profits, monies, accruals, increments or other benefits derived or received by
Executive or any associated party deriving such benefits as a result of any such
breach of the Covenants; and (b) to indemnify SGX against any other losses,
damages (including special and consequential damages), costs and expenses,
including actual attorneys' fees and court costs, which may be incurred by them
and which result from or arise out of any such breach or threatened breach of
the Covenants. Both parties agree that the provisions of this paragraph 12 will
not adequately compensate SGX for SGX' injury in the event of Executive's breach
of any of the Covenants. Accordingly, the parties agree the provisions of this
paragraph 12 will not in any way limit or interfere with SGX' right to seek
injunctive relief under paragraph 11.

     13. Return of SGX Property. On termination of employment with SGX for
whatever reason, or at the request of SGX before termination, Executive agrees
to promptly deliver to SGX all records, files, computer disks, memoranda,
documents, lists and other information regarding or containing any Proprietary
Information (as defined in the Confidential Information and Invention Assignment
Agreement executed herewith), including all copies, reproductions, summaries or
excerpts thereof, then in Executive's possession or control, whether prepared by
Executive or others. Executive also agrees to promptly return, upon termination
or at any time upon SGX' request, any and all SGX property issued to Executive,
including but not limited to computers, facsimile transmission equipment,
cellular phones, keys and credits cards. Executive further agrees that should
Executive discover any SGX property or Proprietary Information in Executive's
possession after Executive's termination and departure from SGX, Executive
agrees to return it promptly to SGX without retaining copies or excerpts of any
kind.

     14. No Violation of Rights of Third Parties. Executive warrants that
Executive's performance of all the terms of this Agreement does not and will not
breach any agreement to keep in confidence proprietary information, knowledge or
data acquired by Executive prior to Executive's employment with SGX. Executive
agrees not to disclose to SGX, or induce SGX to use, any confidential or
proprietary information or material belonging to any previous employers or
others. Executive warrants that Executive is not a party to any other agreement
that will interfere with Executive's full compliance with this Agreement.
Executive further agrees not to enter into any agreement, whether written or
oral, in conflict with the provisions of this Agreement.

     15. Agreement to Arbitrate. Executive and SGX agree to arbitrate any
controversy, claim or dispute between them arising out of or in any way related
to this Agreement, the employment relationship between them, and any disputes
upon termination of employment, except as provided in subparagraph 15.1 below,
to the fullest extent permitted by law. This method of resolving disputes shall
be the sole and exclusive remedy of the parties. Accordingly, the parties
understand that, except as provided in this paragraph 15 or as otherwise
required by law, they are giving up their rights to have their disputes decided
in a court of law and, if applicable, by a jury, and instead agree that their
disputes shall be decided by arbitration.

          15.1. Scope of the Agreement. The disputes subject to this agreement
to arbitrate include all potential claims between Executive and SGX relating to
employment, such as breach of contract, tort, discrimination, harassment,
wrongful termination, demotion, discipline, failure to accommodate, family and
medical leave, compensation or benefits claims, constitutional claims and claims
for violation of any local, state or federal law, statute, regulation or
ordinance or common law to the fullest extent permitted by law. Claims for
workers' compensation or unemployment insurance benefits, if any, and SGX' right
to obtain injunctive relief pursuant to paragraph 11 above are excluded. For the
purposes of this agreement to arbitrate, references to "SGX" include SGX and all
subsidiary and related entities and their employees, supervisors, officers,
directors, owners, agents, benefit plans, benefit plan sponsors, fiduciaries,
administrators, affiliates and all successors and assigns of any of them, and
this agreement to arbitrate shall apply to them to the extent Executive's claims
arise out of or relate to their actions on behalf of SGX.

          15.2. Initiation of Arbitration. Either party may exercise the right
to arbitrate by providing the other party with written notice of any and all
claims forming the basis of such right in sufficient detail to inform the other
party of the substance of such claims.

          15.3. Arbitration Procedure. The arbitration will be conducted in
accordance with the then current rules for resolution of employment disputes of
the American Arbitration Association ("AAA") at its offices

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in San Diego, California. If the parties cannot agree on the single neutral
arbitrator, such arbitrator shall be selected in accordance with the AAA rules.
The parties are entitled to representation by an attorney or other
representative of their choosing. The parties will also be permitted to conduct
discovery sufficient to present their respective cases. The arbitrator will be
required to issue a written arbitration decision that will reveal the essential
findings and conclusions on which an award is based, and shall have the power to
enter any award that could be entered by a judge of the Superior Court of the
State of California, and only such power, and shall follow the law. In the event
the arbitrator does not follow the law, the arbitrator will have exceeded the
scope of his or her authority and the parties may, at their option, file a
motion to vacate the award in court. Otherwise, the parties agree to abide by
and perform any award rendered by the arbitrator. Judgment on the award may be
entered in any court having jurisdiction thereof.

     16. General Provisions.

          16.1. Successors and Assigns. The rights and obligations of SGX under
this Agreement shall inure to the benefit of and shall be binding upon the
successors and assigns of SGX. Executive shall not be entitled to assign any of
Executive's rights or obligations under this Agreement other than to the estate
of Executive.

          16.2. Waiver. Either party's failure to enforce any provision of this
Agreement shall not in any way be construed as a waiver of any such provision,
or prevent that party thereafter from enforcing each and every other provision
of this Agreement.

          16.3. Severability. In the event any provision of this Agreement is
found to be unenforceable by an arbitrator or court of competent jurisdiction,
such provision shall be deemed modified to the extent necessary to allow
enforceability of the provision as so limited, it being intended that the
parties shall receive the benefit contemplated herein to the fullest extent
permitted by law. If a deemed modification is not satisfactory in the judgment
of such arbitrator or court, the unenforceable provision shall be deemed
deleted, and the validity and enforceability of the remaining provisions shall
not be affected thereby.

          16.4. Interpretation; Construction. The headings set forth in this
Agreement are for convenience only and shall not be used in interpreting this
Agreement. This Agreement has been drafted by legal counsel representing SGX,
but Executive has participated in the negotiation of its terms. Furthermore,
Executive acknowledges that Executive has had an opportunity to review and
revise the Agreement and have it reviewed by legal counsel, if desired, and,
therefore, the normal rule of construction to the effect that any ambiguities
are to be resolved against the drafting party shall not be employed in the
interpretation of this Agreement.

          16.5. Governing Law. This Agreement will be governed by and construed
in accordance with the laws of the United States and the State of California.
Each party consents to the jurisdiction and venue of the state or federal courts
in the State where Executive is employed, in any action, suit, or proceeding
arising out of or relating to this Agreement.

          16.6. Notices. Any notice required or permitted by this Agreement
shall be in writing and shall be delivered as follows with notice deemed given
as indicated: (a) by personal delivery when delivered personally; (b) by
overnight courier upon written verification of receipt; (c) by telecopy or
facsimile transmission upon acknowledgment of receipt of electronic
transmission; or (d) by certified or registered mail, return receipt requested,
upon verification of receipt. Notice shall be sent to the addresses set forth
below, or such other address as either party may specify in writing.

          16.7. Survival. Paragraphs 8 ("Competitive Employment"), 9
("Confidentiality and Proprietary Rights"), 10 ("Non-Solicitation"), 11
("Injunctive Relief"), 12 ("Accounting and Indemnification"), 13 ("Return of SGX
Property"), 15 ("Agreement to Arbitrate"), 16 ("General Provisions") and 17
("Entire Agreement") of this Agreement shall survive Executive's employment by
SGX.

     17. Entire Agreement. This Agreement, including SGX' Incentive Plan, bonus
program and Confidential Information and Invention Assignment Agreement herein
incorporated by reference, constitutes the entire agreement between the parties
relating to this subject matter and supersedes all prior or simultaneous
representations, discussions, negotiations, and agreements, whether written or
oral, including but not limited to the Offer Letter of July 16, 2001 and the
Prior Agreement. This Agreement may be amended or modified only with the written
consent of Executive and the Board. No oral waiver, amendment or modification
will be effective under any circumstances whatsoever.

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THE PARTIES TO THIS AGREEMENT HAVE READ THE FOREGOING AGREEMENT AND FULLY
UNDERSTAND EACH AND EVERY PROVISION CONTAINED HEREIN. WHEREFORE, THE PARTIES
HAVE EXECUTED THIS AGREEMENT ON THE DATES SHOWN BELOW.

                                                      Executive

Dated: February __, 2005                              /s/ Michael Grey
                                                      --------------------------
                                                      Michael Grey

                                                      Structural GenomiX, Inc.

Dated: February __, 2005                              By: /s/ Alex Barkas
                                                          ----------------------

                                                      Its: _____________________<PAGE>

                                                                    EXHIBIT 10.7

                         EXECUTIVE EMPLOYMENT AGREEMENT

     This Executive Employment Agreement ("Agreement"), dated January 1, 2002,
by and between Structural GenomiX, Inc., with its principal place of business at
10505 Roselle Street, San Diego, California 92121 ("SGX"), a Delaware
corporation, and Stephen Burley, M.D., D. Phil., who resides at ________________
__________________________________________ ("Executive").

     The parties agree as follows:

     1. Employment. SGX hereby employs Executive, and Executive hereby accepts
such employment, upon the terms and conditions set forth herein.

     2. Duties.

          2.1. Position; Duties and Responsibilities. Executive is employed in
the position of Senior Vice President of Research and Chief Scientific Officer
and shall have the duties and responsibilities assigned by SGX. Executive is
responsible for directing all research and development strategies and programs
to insure that activities are carried out in accordance with established
specifications, schedules, and budgets. Executive shall serve as a key member of
the executive team, as the principal advisor to the team on the scientific
vision and direction for the Company, including overall management of the
Company's core technology and shall report directly to the Chief Executive
Officer. Executive shall perform faithfully and diligently such duties, as well
as such other duties as SGX shall reasonably assign from time to time. SGX
reserves the right to modify Executive's position and duties at any time in its
sole and reasonable discretion, provided that such modified position is an
executive position of at least the same general scope and responsibilities as
originally provided herein.

          2.2 Best Efforts/Full-time. Executive will expend Executive's best
reasonable efforts on behalf of SGX, and will abide by all policies and
decisions made by SGX, as well as all applicable federal, state and local laws,
regulations or ordinances. Executive will act in the best interest of SGX at all
times. Other than as provided in Exhibit "A" hereto, Executive shall devote
Executive's full business time and efforts to the performance of Executive's
assigned duties, unless Executive notifies SGX in advance of Executive's intent
to engage in other paid work and receives SGX' express written consent to do so.
Executive must not engage in any work, paid or unpaid, that creates an actual or
potential conflict of interest with SGX. If SGX believes a conflict exists, and
presents Executive with reasonable proof of the same, SGX may ask Executive to
choose whether to discontinue the other work or resign employment with SGX.

          2.3. Work Location and Effective Date. Executive's principal place of
work shall be located in San Diego, California, at SGX' offices or as reasonably
assigned by SGX. Executive will use his best efforts to take up residence at the
Work Location by January 1, 2002, but in any case shall arrive and start work no
later than January 29, 2002. This Agreement shall be effective ("Effective
Date") on Executive's start date of employment with SGX.

          3. Term. The employment relationship pursuant to this Agreement shall
be for an initial term commencing on the Effective Date set forth above and
continuing for the period of three (3) years and for consecutive one (1) year
terms thereafter unless sooner terminated in accordance with paragraph 7 below.

     4. Compensation.

          4.1. Salary. As compensation for the proper and satisfactory
performance of all duties to be performed by Executive hereunder, SGX shall pay
to Executive an initial annualized Base Salary of Three Hundred Thousand
($300,000), payable in accordance with the normal payroll practices of SGX, less
required deductions for state and federal withholding tax, social security and
all other employment taxes and payroll deductions. Other than as provided in
Article 7 herein, in the event Executive's employment under this Agreement is
terminated by either party, for any reason, Executive will be entitled to
receive the Base Salary prorated to the date of termination.

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          4.2. Incentive Compensation. Executive will be eligible to receive
incentive compensation. If SGX, in its sole and absolute discretion, grants
executive incentive compensation, the terms, amount and payment of such, if any,
will be determined solely by SGX.

          4.3. Stock Options. Executive will receive an option to purchase
200,000 shares of SGX common stock at a price per share equal to its fair market
value as of first meeting of the Board of Directors (the "Board") immediately
following or contemporaneous with Executive's start date, as determined by the
Board in its sole and absolute discretion, with a four year vesting schedule
subject to the terms and conditions of the SGX 2000 Equity Incentive Plan (the
"Incentive Plan"). The effective grant date of the options is the start date of
employment. The offer of these shares is conditioned upon Executive's acceptance
of SGX' offer of employment and will be in accordance with the terms and
requirements of the Incentive Plan and the Company's form of stock option
agreement.

          4.4. Conditional Compensation. In recognition of Executive's
acceptance of employment with SGX under the terms and conditions of this
Agreement, Executive will receive a one-time payment of one hundred thousand
dollars $100,000 ("Payment"), included in Executive's first SGX paycheck, and
subject to appropriate federal, state, and payroll tax withholdings. This
Payment will be subject to the following conditions: (1) if prior to the first
anniversary of the Effective Date, Executive voluntarily terminates Executive's
employment pursuant to paragraph 7.3 below, or (2) Executive is terminated for
cause pursuant to paragraph 7.1 below, Executive will reimburse SGX the full
amount of the Payment at the time of termination.

          4.5. Bonus Stock Options. Executive will receive an additional option
to purchase 40,000 shares of SGX common stock at a price per share equal to its
fair market value as of the first meeting of the Board immediately following or
contemporaneous with Executive's start date, as determined by the Board in its
sole and absolute discretion. These options will vest as of the grant date and
otherwise be subject to the terms and conditions of the Incentive Plan. The
effective grant date is the start date of employment. The offer of these shares
is conditioned upon Executive's acceptance of SGX' offer of employment and will
be in accordance with the terms and requirements of the Incentive Plan and the
Company's form of stock option agreement.

          4.6. Additional Stock Options. To the extent that any of the options
Executive received in Executive's capacity as a Founder of Prospect Genomics,
Inc. do not vest as a result of some or all of the Earnout Milestones (as set
forth in Section 1.9(a) of the Agreement and Plan of Merger and Reorganization
among Structural GenomiX, Inc., SGX Acquisition Corp., and Prospect Genomics,
Inc. dated as of April 2, 2001) not being achieved, SGX will grant Executive an
option to purchase additional shares of common stock. The number of shares which
will be subject to this option will equal the number of shares which did not
vest as a result of the Earnout Milestones not being fully achieved, up to a
maximum of 112,168 shares. The grant of this option will be subject to approval
by the Board and the price per share will equal the fair market value of SGX'
common stock as of the first meeting of the Board immediately following or
contemporaneous with Executive's start date. The offer of these shares will be
subject to the terms and requirements of the Incentive Plan and the Company's
form of stock option agreement.

          4.7 Cash Bonus Program. As Senior Vice President of Research and Chief
Scientific Officer, Executive is eligible to earn a cash bonus equal to 30% of
Executive's base salary, or $90,000 in year one (1), provided Executive meets
the eligibility requirements and performance objectives set forth in SGX' bonus
program, which are determined in SGX' sole and absolute discretion.

          4.8 Performance and Salary Review. SGX will periodically review
Executive's performance. Executive's salary and/or other compensation will be
reviewed yearly by SGX and may be adjusted from time to time in SGX' sole and
absolute discretion.

          4.9. Loan Payment. SGX will provide to Executive the sum of three
hundred thousand dollars ($300,000) constituting an interest-free unforgivable
personal loan to Executive (the "Loan") subject to the terms and conditions of
the Burley Employee Loan Agreement ("Loan Agreement").

     5. Benefits.

<PAGE>

          5.1  Fringe Benefits. Executive will be eligible for all customary and
usual fringe benefits generally available to executives of SGX subject to the
terms and conditions of SGX' benefit plan documents, including, but not limited
to, medical, dental, vision, life insurance, AD&D insurance, long-term and
short-term disability insurance and a 401(k) plan. SGX reserves the right to
modify or eliminate the fringe benefits on a prospective basis, at any time,
effective upon notice to Executive. Executive shall accrue vacation on a pay
period basis at the annual rate of one-hundred-twenty (120) hours. SGX shall
also provide Executive with five (5) days of sick time per year. SGX covenants
that it has, and at all times will maintain, adequate insurance, including
liability insurance and Director's and Officer's insurance to cover any claim or
obligation that Executive may reasonably be expected to incur as a result of his
employment by SGX. Further, SGX shall indemnify and defend Executive against any
claims, demands, liability, suits, losses, damages (including special, punitive,
incidental and consequential damages), costs and expenses, including actual
attorneys' fees and court costs, which may be incurred by him and which result
from his employment as an executive, officer and employee of SGX.

          5.2  Relocation Expenses and Benefits.

               (a)  SGX shall reimburse Executive for expenses related to the
                    relocation of Executive and his family to San Diego as
                    follows:

               (i)  Reasonable travel and living expenses associated with one
                    (1) trip of up to seven (7) days (including travel) to San
                    Diego for the purpose of securing a temporary place to live.
                    If needed, a second trip of like scope will be made
                    available upon reasonable request. Original receipts are
                    required for reimbursement.

               (ii) Reasonably documented moving expenses up to thirty-five
                    thousand dollars ($35,000) (including packing, shipping and
                    temporary storage of household goods and one family
                    vehicle).

               (iii) Up to six (6) months of temporary housing and costs
                    associated with a rental car until Executive's vehicle
                    arrives in San Diego.

               (iv) Normal and customary non-recurring closing costs, including
                    sales commissions, Coop Board Fees and attorney fees, for
                    the sale of Executive's apartment in New York City, up to
                    ten percent (10%) of the price of the apartment. Executive
                    shall provide SGX with reasonable documentation
                    substantiating the costs associated with the sale of
                    Executive's New York apartment.

               (v)  Normal and customary non-recurring closing costs, including
                    sales commissions and attorney fees, associated with the
                    purchase of Executive's new home in San Diego up to three
                    percent (3%) of the purchase price.

               (vi) Reasonable transportation costs for Executive and his family
                    associated with their final move trip to San Diego.

               (vii) SGX will provide Executive with a moving allowance of
                    twenty thousand dollars ($20,000), to be paid with
                    Executive's first paycheck, and subject to appropriate
                    federal, state, and payroll tax withholdings, from SGX.

               (viii) SGX will provide Executive with a company paid-for
                    relocation consultant to provide Executive with a variety of
                    relocation assistance, including, but not limited to,
                    finding a moving company, interim housing, real estate
                    professionals and information about the San Diego area.

<PAGE>

               (b)  SGX will gross-up all of the reimbursements, payments and
                    costs of services described in 5.2(a) above, except for item
                    (vii), (to the extent such items are considered taxable
                    income) for income and employment taxes. The income tax
                    gross-up will be calculated using the supplemental wage
                    rates in effect when payment is made. SGX will be reimbursed
                    for the pro-rated portion of the above payments and costs
                    from Executive, other than the services provided by the
                    relocation consultant, should Executive's employment be
                    terminated prior to the completion of one (1) year of
                    service pursuant to subparagraphs 7.1 or 7.3 herein. SGX
                    shall withhold such amount from Executive's final paycheck.

          5.3  Interim Consultation. Prior to Executive's relocation and start
               date with SGX, Executive will continue to provide SGX with
               consulting services, and receive payment for the same, under the
               Executive's Founding Scientific Associate and Consulting
               Agreement with Prospect Genomics, Inc., of March 1, 2000, as
               amended on May 4, 2001. Executive's interim consultation will be
               for the exchange of ideas only. Under no circumstances, will
               Executive direct research at SGX prior to his start date of
               employment.

     6.   Business Expenses. Executive will be reimbursed for all out-of-pocket
business expenses reasonably incurred in the performance of Executive's duties
on behalf of SGX. Executive will be permitted to fly business class (or first
class if business class is not available) on any business flights with greater
than two (2) hours of flight time. To obtain reimbursement, expenses must be
submitted promptly with appropriate supporting documentation in accordance with
SGX' policies.

     7.   Termination of Employment.

          7.1. Termination for Cause by SGX. Although SGX anticipates a mutually
rewarding employment relationship with Executive, SGX may terminate Executive's
employment immediately at any time for cause. Cause includes, but is not limited
to, one or more of the following: (a) acts or omissions deemed by SGX to
constitute gross negligence, recklessness, willful misconduct or dishonesty on
the part of Executive with respect to Executive's obligations under this
Agreement or otherwise relating to the business of SGX; (b) Executive's willful,
material breach of this Agreement; (c) Executive's conviction or entry of a plea
of guilty or nolo contendere for fraud, misappropriation or embezzlement, or of
any felony; or engaging in any conduct which SGX, in its discretion, determines
has or may adversely impact SGX; (d) Executive's material breach of fiduciary
duty toward SGX; (e) Executive's material breach of any element of SGX'
Confidential Information and Invention Assignment Agreement, including without
limitation, Executive's theft, dilution, or other misappropriation or careless
treatment of SGX' proprietary information; (f) Executive's inability to perform
all of the essential functions and duties of Executive's position, with or
without reasonable accommodation other than for reason of temporary illness; or
(g) Executive's death. In the event Executive's employment is terminated in
accordance with this subparagraph 7.1, Executive shall be entitled to receive
only the Base Salary then in effect, prorated to the date of termination, and
any benefits, including any benefits under the bonus program and Incentive Plan,
and expense reimbursements to which Executive is entitled by virtue of his prior
employment with SGX (collectively referred to as "Standard Entitlements."). All
other SGX obligations to Executive pursuant to this Agreement will become
automatically terminated and completely extinguished. Executive will not be
entitled to receive the Severance Payment or any part thereof described in
subparagraph 7.2 below.

          7.2. Termination Without Cause By SGX/Severance. SGX may terminate
Executive's employment under this Agreement without cause at any time on thirty
(30) days' advance written notice to Executive, including the failure of SGX to
renew Executive's term of employment under paragraph 3 of this Agreement. In the
event of such termination, Executive will receive the Standard Entitlements,
plus a severance payment equivalent to twelve months of Executive's Base Salary
then in effect on the date of termination (the "Severance Payment") payable in
accordance with SGX' regular payroll cycle, including continuation of
Executive's benefits in accordance with SGX's regular payroll deductions. In
addition, the vesting of any outstanding stock options, including, but not
limited to, options granted under paragraphs 4.3 and 4.6, as well as any
subsequently granted incentive or evergreen stock options, will be accelerated
by 12 months, provided that Executive: (a) is in material compliance with all
surviving provisions of this Agreement as specified in

<PAGE>

subparagraph 16.7 below; (b) executes a full general release, releasing all
claims, known or unknown, that Executive may have against SGX arising out of or
any way related to Executive's employment or termination of employment with SGX;
and (c) agrees to act as a consultant for SGX for up to a maximum of sixty (60)
days, without additional compensation, if requested to do so by SGX. All other
SGX obligations to Executive pursuant to this Agreement will become
automatically terminated and completely extinguished, except for obligations
accruing prior to termination, including SGX's obligation to indemnify, defend
and insure Executive pursuant to subparagraph 5.1 hereunder.

          7.3. Voluntary Resignation By Executive. Executive may voluntarily
resign Executive's position with SGX at any time on thirty (30) days advance
written notice. In the event of Executive's resignation, Executive shall be
entitled to receive only the Base Salary then in effect, prorated to the date of
resignation, and the Standard Entitlements. All other SGX obligations to
Executive pursuant to this Agreement will become automatically terminated and
completely extinguished, except for obligations accruing prior to termination,
including SGX's obligation to indemnify, defend and insure Executive pursuant to
subparagraph 5.1 hereunder. In addition, Executive will not be entitled to
receive the Severance Payment described in paragraph 7.2 above.

          7.4. Termination of Executive Following Change Of Control.

               (a)  Severance Payment. If Executive's employment is terminated
by SGX without cause, or if Executive resigns because SGX substantially changes
all of Executive's duties and responsibilities which existed prior to a Change
in control, within one (1) year after a Change of Control (as that term is
defined below), Executive shall be entitled to receive the Standard
Entitlements, plus the Severance Payment and other benefits described in
subparagraph 7.2 above, and the vesting of any outstanding stock options,
including, but not limited to, options granted under paragraphs 4.3 and 4.6, as
well as any subsequently granted incentive or evergreen stock options, will be
accelerated by twenty-four (24) months, provided Executive complies with the
conditions in subparagraph 7.2 above. All other SGX obligations to Executive
pursuant to this Agreement will become automatically terminated and completely
extinguished, except for obligations accruing prior to termination, including
SGX's obligation to indemnify, defend and insure Executive pursuant to
subparagraph 5.1 hereunder.

               (b)  280G. If, due to the benefits provided under subparagraph
7.4(a) above, and/or any other benefits, Executive is subject to any excise tax
due to characterization of any amounts payable under subparagraph 7.4(a) and/or
any other benefits, as excess parachute payments pursuant to Section 4999 of the
Internal Revenue Code of 1986, as amended (the "Code"), Executive may elect, in
Executive's sole discretion, to reduce the amounts payable under subparagraph
7.4(a)and/or any other benefits, in order to avoid any "excess parachute
payment" under Section 280G(b)(1) of the Code.

               (c)  Change of Control. A Change of Control is defined as any one
of the following occurrences:

                    (i)  Any "person" (as such term is used in Sections 13(d)
and 14(d) of the Securities Exchange Act of 1934 (the "Exchange Act")), other
than a trustee or other fiduciary holding securities of SGX under an employee
benefit plan of SGX, becomes the "beneficial owner" (as defined in Rule 13d-3
promulgated under the Exchange Act), directly or indirectly, of the securities
of SGX representing more than 50% of (a) the outstanding shares of common stock
of SGX or (b) the combined voting power of SGX' then-outstanding securities; or

                    (ii) The sale or disposition of all or substantially all of
SGX' assets (or any transaction having similar effect is consummated) other than
to an entity of which SGX owns at least 50% of the Voting Stock so long as the
sale or disposition is not under duress of SGX' financial hardship; or

                    (iii) SGX is party to a merger or consolidation that results
in the holders of voting securities of SGX outstanding immediately prior thereto
failing to continue to represent (either by remaining outstanding or by being
converted into voting securities of the surviving entity) less than 50% of the
combined voting power of the voting securities of SGX or such surviving entity
outstanding immediately after such merger or consolidation.

<PAGE>

     8.   Competitive Employment. During the term of Executive's employment with
SGX and during any period in which Executive is receiving payments (other than
any dividends on stock) from SGX or acting as a consultant with or without
payment, Executive agrees that Executive will not knowingly directly compete
with SGX in any way, and will not, subject to subparagraph 2.2 and Exhibit A
herein, act as an officer, director, executive, consultant, shareholder (other
than stock of publicly held companies), volunteer, lender, or agent of any
business enterprise of the same nature as, or which is in direct competition
with, the business in which SGX is now engaged or in which SGX becomes engaged
during the term of Executive's employment with SGX, as may be determined by SGX
in its sole reasonable discretion. Further, Executive agrees not to refer any
client or potential client to competitors of SGX without SGX' written consent
during the term of Executive's employment with SGX or during any period in which
Executive is receiving payments (other than any dividends on stock) from SGX or
acting as a paid consultant.

     9.   Confidentiality and Proprietary Rights. Executive agrees to abide by
SGX' proprietary rights policies and to protect the intellectual property of
SGX. In accordance, Executive will sign, prior to the Effective Date of this
Agreement, a Confidential Information and Invention Assignment Agreement, which
is incorporated herein by this reference.

     10.  Non-Solicitation.

          10.1. Non-Solicitation of Employees and Independent Contractors.
Executive agrees that during Executive's employment with SGX and for a period of
one (1) year after the termination of Executive's employment with SGX, Executive
will not directly or indirectly, separately or in association with others,
knowingly interfere with, impair, disrupt or damage SGX' relationship with any
employee or independent contractor; solicit, encourage or attempt to hire any of
SGX' employees or independent contractors; or cause others to solicit or
encourage any of SGX' employees or independent contractors to discontinue their
employment or services with SGX.

          10.2. Non-Solicitation of Customers. Executive acknowledges that
proprietary information about SGX' customers is confidential and constitutes
trade secrets of SGX. Executive agrees that during Executive's employment with
SGX and for a period of one (1) year following the termination of Executive's
employment with SGX, Executive will not, either directly or indirectly,
separately or in association with others, knowingly do any of the following: (i)
make known, to any person, firm or corporation, the names and addresses of any
of the customers of SGX or contacts of SGX within the pharmaceutical or
biotechnology industries or any other information pertaining to such persons;
(ii) call on, solicit, take away, or attempt to call on, solicit or take away
any of the customers of SGX on whom Executive called or with whom Executive
became aware or acquainted during Executive's association with SGX, whether for
Executive or for any other person, firm or corporation; or (iii) use or make
known to any person or entity, the strategies, tactics, practices, and
procedures by which SGX does business.

     11.  Injunctive Relief. Executive acknowledges that Executive's breach of
the covenants contained in paragraphs 8-10 (collectively "Covenants") could
cause irreparable injury to SGX and agrees that in the event of any such breach,
SGX shall be entitled to seek temporary, preliminary and permanent injunctive
relief without the necessity of proving actual damages or posting any bond or
other security.

     12.  Accounting and Indemnification. In the event Executive breaches any of
the Covenants contained in paragraphs 8-10, SGX shall have the right and remedy
to require Executive to: (a) account for and pay over to SGX all compensation,
profits, monies, accruals, increments or other benefits derived or received by
Executive or any associated party deriving such benefits as a direct result of
any such breach of the Covenants; and (b) to indemnify SGX against any other
losses, damages (including special and consequential damages), costs and
expenses, including actual attorneys' fees and court costs, which may be
incurred by them and which directly result from or arise out of any such breach
or threatened breach of the Covenants. Both parties agree that the provisions of
this paragraph 12 will not adequately compensate SGX for SGX' injury in the
event of Executive's breach of any of the Covenants. Accordingly, the parties
agree the provisions of this paragraph 12 will not in any way limit or interfere
with SGX' right to seek injunctive relief under paragraph 11.

     13.  Return of SGX Property. On termination of employment with SGX for
whatever reason, or at the request of SGX before termination, Executive agrees
to promptly deliver to SGX all records, files, computer disks,

<PAGE>

memoranda, documents, lists and other information regarding or containing any
Proprietary Information, including all copies, reproductions, summaries or
excerpts thereof, then in Executive's possession or control, whether prepared by
Executive or others. Executive also agrees to promptly return, upon termination
or at any time upon SGX' request, any and all SGX property issued to Executive,
including but not limited to computers, facsimile transmission equipment,
cellular phones, keys and credits cards. Executive further agrees that should
Executive discover any SGX property or Proprietary Information in Executive's
possession after Executive's termination and departure from SGX, Executive
agrees to return it promptly to SGX without retaining copies or excerpts of any
kind.

     14.  No Violation of Rights of Third Parties. Executive warrants that, to
the best of his knowledge, Executive's performance of all the terms of this
Agreement does not and will not breach any agreement to keep in confidence
proprietary information, knowledge or data acquired by Executive prior to
Executive's employment with SGX. Executive agrees not to disclose to SGX, or
induce SGX to use, any confidential or proprietary information or material
belonging to any previous employers or others. Executive warrants that, to the
best of his knowledge, Executive is not a party to any other agreement that will
interfere with Executive's full compliance with this Agreement. Executive
further agrees not to enter into any agreement, whether written or oral, in
conflict with the provisions of this Agreement.

     15.  Agreement to Arbitrate. Executive and SGX agree to arbitrate any
controversy, claim or dispute between them arising out of or in any way related
to this Agreement, the employment relationship between them, and any disputes
upon termination of employment, except as provided in subparagraph 15.1 below,
to the fullest extent permitted by law. This method of resolving disputes shall
be the sole and exclusive remedy of the parties. Accordingly, the parties
understand that, except as provided in this paragraph 15 or as otherwise
required by law, they are giving up their rights to have their disputes decided
in a court of law and, if applicable, by a jury, and instead agree that their
disputes shall be decided by arbitration.

          15.1. Scope of the Agreement. The disputes subject to this agreement
to arbitrate include all potential claims between Executive and SGX relating to
employment, such as breach of contract, tort, discrimination, harassment,
wrongful termination, demotion, discipline, failure to accommodate, family and
medical leave, compensation or benefits claims, constitutional claims and claims
for violation of any local, state or federal law, statute, regulation or
ordinance or common law to the fullest extent permitted by law. Claims for
workers' compensation or unemployment insurance benefits, if any, and SGX' right
to obtain injunctive relief pursuant to paragraph 11 above are excluded. For the
purposes of this agreement to arbitrate, references to "SGX" include SGX and all
subsidiary and related entities and their employees, supervisors, officers,
directors, owners, agents, benefit plans, benefit plan sponsors, fiduciaries,
administrators, affiliates and all successors and assigns of any of them, and
this agreement to arbitrate shall apply to them to the extent Executive's claims
arise out of or relate to their actions on behalf of SGX.

          15.2. Initiation of Arbitration. Either party may exercise the right
to arbitrate by providing the other party with written notice of any and all
claims forming the basis of such right in sufficient detail to inform the other
party of the substance of such claims.

          15.3. Arbitration Procedure. The arbitration will be conducted in
accordance with the then current rules for resolution of employment disputes of
the American Arbitration Association ("AAA") at its offices in San Diego,
California. If the parties cannot agree on the single neutral arbitrator, such
arbitrator shall be selected in accordance with the AAA rules. The parties are
entitled to representation by an attorney or other representative of their
choosing. The parties will also be permitted to conduct discovery sufficient to
present their respective cases. The arbitrator will be required to issue a
written arbitration decision that will reveal the essential findings and
conclusions on which an award is based, and shall have the power to enter any
award that could be entered by a judge of the Superior Court of the State of
California, and only such power, and shall follow the law. In the event the
arbitrator does not follow the law, the arbitrator will have exceeded the scope
of his or her authority and the parties may, at their option, file a motion to
vacate the award in court. Otherwise, the parties agree to abide by and perform
any award rendered by the arbitrator. Judgment on the award may be entered in
any court having jurisdiction thereof.

<PAGE>

     16.  General Provisions.

          16.1. Successors and Assigns. The rights and obligations of SGX under
this Agreement shall inure to the benefit of and shall be binding upon the
successors and assigns of SGX. Executive shall not be entitled to assign any of
Executive's rights or obligations under this Agreement other than to the estate
of Executive.

          16.2. Waiver. Either party's failure to enforce any provision of this
Agreement shall not in any way be construed as a waiver of any such provision,
or prevent that party thereafter from enforcing each and every other provision
of this Agreement.

          16.3. Severability. In the event any provision of this Agreement is
found to be unenforceable by an arbitrator or court of competent jurisdiction,
such provision shall be deemed modified to the extent necessary to allow
enforceability of the provision as so limited, it being intended that the
parties shall receive the benefit contemplated herein to the fullest extent
permitted by law. If a deemed modification is not satisfactory in the judgment
of such arbitrator or court, the unenforceable provision shall be deemed
deleted, and the validity and enforceability of the remaining provisions shall
not be affected thereby.

          16.4. Interpretation; Construction. The headings set forth in this
Agreement are for convenience only and shall not be used in interpreting this
Agreement. This Agreement has been drafted by legal counsel representing SGX,
but Executive has participated in the negotiation of its terms. Furthermore,
Executive acknowledges that Executive has had an opportunity to review and
revise the Agreement and have it reviewed by legal counsel, if desired, and,
therefore, the normal rule of construction to the effect that any ambiguities
are to be resolved against the drafting party shall not be employed in the
interpretation of this Agreement.

          16.5. Governing Law. This Agreement will be governed by and construed
in accordance with the laws of the United States and the State of California.
Each party consents to the jurisdiction and venue of the state or federal courts
in the State where Executive is employed, in any action, suit, or proceeding
arising out of or relating to this Agreement.

          16.6. Notices. Any notice required or permitted by this Agreement
shall be in writing and shall be delivered as follows with notice deemed given
as indicated: (a) by personal delivery when delivered personally; (b) by
overnight courier upon written verification of receipt; (c) by telecopy or
facsimile transmission upon acknowledgment of receipt of electronic
transmission; or (d) by certified or registered mail, return receipt requested,
upon verification of receipt. Notice shall be sent to the addresses set forth
below, or such other address as either party may specify in writing.

          16.7. Survival. Paragraphs 5.1 ("Benefits", with respect to SGX's
insurance and indemnity obligations to Executive), 7.2 ("Termination without
Cause by SGX"), 7.4 (Termination of Executive Following Change of Control"), 8
("Competitive Employment"), 9 ("Confidentiality and Proprietary Rights"), 10
("Non-Solicitation"), 11 ("Injunctive Relief"), 12 ("Accounting and
Indemnification"), 13 ("Return of SGX Property") 15 ("Agreement to Arbitrate"),
16 ("General Provisions") and 17 ("Entire Agreement") of this Agreement shall
survive Executive's employment by SGX.

     17.  Entire Agreement. This Agreement, including the Incentive Plan, bonus
program, Employee Loan Agreement and Confidential Information and Invention
Assignment Agreement herein incorporated by reference, constitutes the entire
agreement between the parties relating to this subject matter and supersedes all
prior or simultaneous representations, discussions, negotiations, and
agreements, whether written or oral, including but not limited to the Offer
Letter of August 31, 2001. This Agreement may be amended or modified only with
the written consent of Executive and the Board of Directors of SGX. No oral
waiver, amendment or modification will be effective under any circumstances
whatsoever. Termination of Executive's employment and/or this Agreement, for any
reason, or under any of the provisions of Article 7, shall not impact any other
agreements between Executive and SGX, including, but not limited to, the
Founding Scientific Associate and Consulting Agreement of March 1, 2000 (with
Prospect Genomics, Inc.), as amended on May 4, 2001 (between Prospect Genomics,
Inc., Structural GenomiX, Inc. and Executive)("Founders Agreement"). Executive's
continuing employment with SGX shall satisfy all of his consulting obligations
to SGX pursuant to the Founders Agreement.

<PAGE>

THE PARTIES TO THIS AGREEMENT HAVE READ THE FOREGOING AGREEMENT AND FULLY
UNDERSTAND EACH AND EVERY PROVISION CONTAINED HEREIN. WHEREFORE, THE PARTIES
HAVE EXECUTED THIS AGREEMENT ON THE DATES SHOWN BELOW.

                                                Executive

Dated: January 28, 2002                         /s/ Stephen Burley
                                                --------------------------------
                                                Stephen Burley, M.D., D. Phil.

                                                Structural GenomiX Inc.

Dated: January 28, 2002                         By: /s/ Tim Harris
                                                    ----------------------------

                                                Its: President and CEO

<PAGE>

                                    EXHIBIT A

    EXCEPTIONS TO EXECUTIVE'S FULL-TIME COMMITMENTS PURSUANT TO PARAGRAPH 2.2

1. Subject to the approval of the NIGMS, continue to serve as the Principal
Investigator on the NIGMS P50 Center Grant (the "Grant"), assuming that NIGMS
will allow the transfer of at least a part of the Grant to SGX (typical service
= TBD; may result in up to $3,000,000 in payments to SGX per year).

2. Continued service as the Chair, Scientific Advisory Board of the Protein Data
Bank (typical service = 1 meeting per year).

3. Continued service as the Chair, Scientific Advisory Board of Protein
Solutions Inc. (typical service = 1 meeting per year).

4. Continued service as a Member, Scientific Advisory Committee of the DIAMOND
Synchrotron Project in the UK (typical service = 2-3 meetings per year).

5. Continued service as a Member, Chemical Biology Advisory Board of the
American Association of Cancer Research (typical service = 1-2 meetings per
year).

6. Continued service as a Member, various Editorial Advisory Boards for
scientific journals (typical service = minimal).
<PAGE>
                           Relocation Loan Agreement

      This Relocation Loan Agreement ("Agreement", also referred to as "Note")
is effective as of July 29, 2002 ("Effective Date"), by and between Structural
GenomiX, Inc., a Delaware corporation with its principal place of business at
10505 Roselle Street, San Diego, California 92121 ("SGX", also referred to as
"Holder"), and Stephen Burley, M.D., D. Phil., an individual who resides at
____________________________________ ("Burley", also referred to as "Maker")
(each a "Party" and collectively the "Parties").

                                    RECITALS

      A.    WHEREAS, SGX has employed Burley as Chief Scientific Officer and
            Senior Vice President of Research.

      B.    WHEREAS, Burley has relocated to San Diego to perform his duties as
            an SGX employee.

      C.    WHEREAS, SGX hereby provides a relocation loan of three hundred
            thousand dollars ($300,000) to Burley to be used solely for the
            purchase of his new principal residence, subject to the terms of
            this Agreement;

      NOW THEREFORE, in consideration of the mutual covenants and conditions set
forth hereunder, the Parties hereby agree as follows:

                                    AGREEMENT

1.    SGX'S OBLIGATIONS.

      1.1   Loan Payment. SGX will provide to Burley, for the purchase of a new
principal residence by Burley, three hundred thousand dollars ($300,000)
constituting an interest-free relocation loan to Burley (the "Loan").

2.    BURLEY'S OBLIGATIONS.

      2.1   Repayment Obligation. Burley, for value received, hereby promises to
pay SGX at its principle place of business, the principal sum of three hundred
thousand dollars ($300,000) consistent with this Agreement. Subject to the Early
Recall terms and conditions of paragraphs 2.2 and 2.3, Burley will pay to SGX
the full Loan amount of $300,000 (Non-Forgivable) in equal increments of
twenty-five percent (25%) or $75,000, on each of four consecutive semi-annual
payment dates commencing January 1, 2012 as follows:

                  (a)   $75,000 due on January 1, 2012 to SGX at 10505 Roselle
      Street, San Diego, California 92121, or at such other place as SGX may
      designate in writing, in lawful money of the United States of America and
      in immediately available funds.

                                  Page 1 of 7
<PAGE>

                  (b)   $75,000 due on July l, 2012 so long as Burley is
      employed by SGX on that date. However, upon termination of Burley's
      employment at any time during the six (6) month period after January 1,
      2012 but prior to July 1, 2012, Burley will immediately pay the balance of
      the Loan principal, presumably $225,000, to SGX at 10505 Roselle Street,
      San Diego, California 92121, or at such other place as SGX may designate
      in writing, in lawful money of the United States of America and in
      immediately available funds.

                  (c)   $75,000 due on January 1, 2013 so long as Burley is
      employed by SGX on that date. However, upon termination of Burley's
      employment at any time during the six (6) month period after July 1, 2012
      but prior to January 1, 2013, Burley will immediately pay the balance of
      the Loan principal, presumably $150,000, to SGX at 10505 Roselle Street,
      San Diego, California 92121, or at such other place as SGX may designate
      in writing, in lawful money of the United States of America and in
      immediately available funds.

                  (d)   $75,000 due on July 1, 2013 so long as Burley is
      employed by SGX on that date. However, upon termination of Burley's
      employment at any time during the six (6) month period after January 1,
      2013 but prior to July 1, 2013, Burley will immediately pay the balance of
      the Loan principal, presumably $75,000, to SGX at 10505 Roselle Street,
      San Diego, California 92121, or at such other place as SGX may designate
      in writing, in lawful money of the United States of America and in
      immediately available funds.

      2.2   Early Recall. At any time within one year after the occurrence of an
event listed in this paragraph ("Recall Event"), and subject to the Default
provisions of paragraph 3, SGX shall have the right to demand repayment of the
Loan in accordance with paragraph 2.3 below. A Recall Event is deemed to have
occurred upon:

                  (a)   an initial public offering of SGX stock; or

                  (b)   a merger, acquisition, or sale ("Transaction") of SGX to
      or into any publicly traded company, or any subsidiary of a publicly
      traded company, whereby SGX stockholders receive publicly traded stock in
      connection with the Transaction; or

                  (c)   termination of Burley's employment pursuant to the
      Burley/SGX Employment Agreement.

      2.3   Early Recall Repayment of Loan. Immediately upon the date of SGX's
demand for repayment pursuant to paragraph 2.2 ("Recall Date"), Burley will pay
to SGX the full Loan amount of $300,000 (Non-Forgivable) in equal increments of
twenty-five percent (25%) or $75,000, on each of four consecutive semi-annual
payment dates commencing six (6) months after the Recall Date as follows:

                  (a)   $75,000 due six (6) months after the Recall Date, so
      long as Burley is employed by SGX on that date. However, upon termination
      of Burley's employment at any time during the first six (6) month period,
      Burley will immediately

                                  Page 2 of 7
<PAGE>

      pay the full principal amount of the $300,000 to SGX at 10505 Roselle
      Street, San Diego, California 92121, or at such other place as SGX may
      designate in writing, in lawful money of the United States of America and
      in immediately available funds.

                  (b)   $75,000 due twelve (12) months after the Recall Date, so
      long as Burley is employed by SGX on that date. However, upon termination
      of Burley's employment at any time during the second six (6) month period,
      Burley will immediately pay the balance of the Loan principal, presumably
      $225,000 to SGX at 10505 Roselle Street, San Diego, California 92121, or
      at such other place as SGX may designate in writing, in lawful money of
      the United States of America and in immediately available funds.

                  (c)   $75,000 due eighteen (18) months after the Recall Date,
      so long as Burley is employed by SGX on that date. However, upon
      termination of Burley's employment at any time during the third six (6)
      month period, Burley will immediately pay the balance of the Loan
      principal, presumably $150,000, to SGX at 10505 Roselle Street, San Diego,
      California 92121, or at such other place as SGX may designate in writing,
      in lawful money of the United States of America and in immediately
      available funds.

                  (d)   $75,000 due twenty-four (24) months after the Recall
      Date, so long as Burley is employed by SGX on that date. However, upon
      termination of Burley's employment at any time during the fourth six (6)
      month period, Burley will immediately pay the balance of the Loan
      principal, presumably $75,000, to SGX at 10505 Roselle Street, San Diego,
      California 92121, or at such other place as SGX may designate in writing,
      in lawful money of the United States of America and in immediately
      available funds.

      2.4   Services. This Loan is conditioned upon the performance of Burley's
service as an employee of SGX. The benefits of the favorable interest on this
Loan cannot be transferred by Burley.

      2.5   Deductions. Burley hereby certifies that he reasonably expects to be
entitled to and will itemize deductions for each year this Loan is outstanding.

      2.6   Security. This Note is secured by a deed of trust ("Deed of Trust")
signed by Burley and his spouse ("Maker"), as trustor, naming Holder as
beneficiary and Chicago Title Company as trustee. Reference is made to the Deed
of Trust for a description of the security and for a statement of the terms and
conditions upon which this Note is secured. The Deed of Trust securing this Note
contains the following provision:

            If the Trustor shall convey, alienate or encumber the
            property or any portion thereof or any interest therein
            or shall be divested of title in any manner or way,
            whether voluntarily or involuntarily, any indebtedness
            or obligation secured hereby, at the option of
            Beneficiary

                                  Page 3 of 7
<PAGE>

            and without demand or notice, shall be due and payable
            immediately.

      2.7   Payment of Taxes, Etc. on Collateral. Burley agrees to pay prior to
delinquency all taxes, charges, liens and assessments against the Collateral,
and upon failure of Burley to do so, SGX at its option may pay any of them and
Burley agrees that SGX shall be the sole judge of the legality or validity
thereof and the amount necessary to discharge the same.

3.    DEFAULT.

      3.1   Events Triggering Default Remedies. The occurrence of one or more of
the following events constitutes a default under this Agreement:

            (a)   Any termination with cause, other than termination caused
      solely by a Change of Control as defined in paragraph 3.2 below, of the
      employment relationship between SGX and Burley by either SGX or Burley;

            (b)   Failure by Burley to keep or perform any of the terms or
      provisions of this Agreement;

            (c)   Burley informs SGX of his intention not to perform or observe
      a term or provision of this Agreement;

            (d)   Levy of any attachment, execution or other process against the
      primary residence; or

            (e)   Insolvency, commission of an act of bankruptcy, general
      assignment for the benefit of creditors, filing of any petition in
      bankruptcy or for relief under the provisions of Title 11 of the United
      States Code of, by, or against Burley.

      3.2   Change of Control Defined. A "Change of Control" is defined as any
one of the following occurrences:

                  (a)   Any "person" (as such term is used in Sections 13(d) and
      14(d) of the Securities Exchange Act of 1934 (the "Exchange Act"), other
      than a trustee or other fiduciary holding securities of SGX under an
      employee benefit plan of SGX, becomes the "beneficial owner" (as such term
      is defined in Rule 13d-3 promulgated under the Exchange Act), directly or
      indirectly, of the securities of SGX representing more than 50% of (1) the
      outstanding shares of common stock of SGX, or (ii) the combined voting
      power of SGX's then-outstanding securities;

                  (b)   The sale or disposition of all or substantially all of
      SGX's assets (or the consummation of any transaction having similar
      effect) other than to an entity of which SGX owns at least 50% of the
      voting stock;

                                  Page 4 of 7
<PAGE>

                  (c)   SGX is party to a merger of consolidation that results
      in the holders of voting securities of SGX outstanding immediately prior
      thereto failing to continue to represent (either by remaining outstanding
      or by being converted into voting securities of the surviving entity) more
      than 50% of the combined voting power of the voting securities of SGX or
      such surviving entity outstanding immediately after such merger or
      consolidation; or

            3.2.1 Change of Control does not include any circumstance which is
not delineated above and specifically does not include any financial hardship
experienced by SGX, including but not limited to the sale of assets under
duress, any bankruptcy, liquidation, or dissolution.

      3.3   Default Remedies.

            3.3.1 Acceleration. On the occurrence of any event enumerated in
Paragraph 3.1 of this Agreement, the amount of the Loan principal remaining
pursuant to Paragraph 2 of this Agreement shall be immediately due and payable
without any action of SGX, Burley, or any other person.

            3.3.2 Other Recourse. If any deficiency remains on the unpaid
balance of the Loan after application of the security, then Burley shall remain
personally liable for payment for the full amount of such deficiency, and SGX
may exercise all rights and remedies available to it under law and in equity.

            3.3.3 Continuing Rights. Until repayment of the Loan in full by
Burley, the power of sale and all other rights, powers and remedies granted to
SGX hereunder shall continue to exist and may be exercised by SGX at any time
and from time to time irrespective any applicable statutes of limitations or
that the personal liability of Burley may have ceased.

                               GENERAL PROVISIONS

4.    EMPLOYMENT OBLIGATIONS UNAFFECTED. This Agreement in no way alters or
      changes the rights and obligations of Burley and SGX pursuant to the
      Employment Relationship. Specifically, the at-will employment relationship
      between SGX and Burley established continues and no term of this Agreement
      alters Burley's at-will relationship with SGX.

5.    STOCK OPTION AGREEMENT AND PLAN UNAFFECTED. This Agreement in no way
      alters or changes the rights and obligations of Burley and SGX pursuant to
      the stock option agreement and plan.

6.    OTHER RIGHTS UNAFFECTED. The rights, powers and remedies given to SGX by
      this Agreement shall be in addition to all rights, powers and remedies
      given to SGX by virtue of any other agreement, statute, or rule of law.

                                  Page 5 of 7
<PAGE>

7.    NONWAIVER OF RIGHTS. Any forbearance, failure or delay by SGX in
      exercising any right, power or remedy hereunder shall not be deemed a
      waiver of such right, power or remedy, and any single or partial exercise
      of any right, power or remedy hereunder shall not preclude the further
      exercise thereof; and every right, power and remedy of SGX shall continue
      in full force and effect until such right, power or remedy is specifically
      waived by an instrument in writing executed by SGX.

8.    ASSIGNMENT AND DELEGATION. SGX can assign this Agreement at its
      discretion. This Agreement, however, may not be assigned or delegated in
      whole or in part by Burley without the prior express written consent of
      SGX. Specifically, Burley cannot assign or transfer the benefits of the
      interest arrangement of this loan.

9.    GOVERNING LAW. Principal and interest are payable in lawful money of the
      United States. This Note has been executed and delivered by Maker in the
      State of California and shall be governed by and construed in accordance
      with the laws of the State of California. In any action brought under or
      arising out of this Note, Maker hereby consents to the jurisdiction of any
      competent court within the State of California and consents to service of
      process by any means authorized by California law.

10.   WAIVER OF BREACH. Either Party's waiver of any breach or default by the
      other Party shall not constitute a waiver of any different or subsequent
      breach or default.

11.   COSTS OF COLLECTION. If the obligation is not paid when due, whether at
      maturity or by acceleration, Burley promises to pay all costs, including
      attorney's fees, incurred by SGX in collecting the amounts due.

12.   UNENFORCEABLE PROVISIONS. If any provision or part of a provision herein
      is held to be invalid, illegal or unenforceable for any reason, such
      invalidity, illegality or unenforceability shall be severed, but without
      in any way affecting the remainder of such provision or any other
      provision contained herein, which shall continue in full force and effect.

13.   ENTIRE AGREEMENT. This Agreement, including the schedules attached hereto,
      constitutes the entire Agreement between the Parties concerning the
      subject matter hereof, supercedes all prior and contemporaneous
      communications or agreements, written or oral, and is intended by the
      Parties to be a complete and exclusive statement of the terms of the
      agreement between them. This Agreement may only be modified by a writing
      signed by authorized representatives of both Parties.

                                  Page 6 of 7
<PAGE>

IN WITNESS WHEREOF, the Parties hereto have caused this Agreement to be executed
in duplicate by their duly authorized representatives.

Structural GenomiX, Inc.:                   Stephen K. Burley, M.D., D.Phil.:

By:         /s/ Tim Harris                        /s/ Stephen K. Burley
   -----------------------------------    --------------------------------------

Name:       Dr. Tim Harris
     ---------------------------------

Title:      CEO & President
      --------------------------------

                                Consent of Spouse

      I, SONIA ESPEJON-REYNES, spouse of Stephen K. Burley, M.D., D.Phil., the
party to this Agreement, acknowledge that I have read the foregoing Relocation
Loan Agreement between Stephen K. Burley, M.D., D.Phil., and Structural GenomiX,
Inc. and know its contents. I consent to, and am aware, that by its terms, the
Agreement is secured by our primary residence which is jointly held by Stephen
K. Burley, M.D., D.Phil. and myself. I agree to be bound by this Agreement and
the Deed of Trust, which I will separately execute, and I will take no action at
any time to hinder the parties' rights to this Agreement or the Deed of Trust.

        /s/ Sonia Espejon-Reynes
----------------------------------------
          SONIA ESPEJON-REYNES

                                   Page 7 of 7

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