MORTGAGE LOAN SALE AND ASSIGNMENT AGREEMENT

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Exhibit 99.1

EXECUTION COPY

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LEHMAN BROTHERS HOLDINGS INC.,

SELLER

and

STRUCTURED ASSET SECURITIES CORPORATION,

PURCHASER

MORTGAGE LOAN SALE AND ASSIGNMENT AGREEMENT

Dated as of December 1, 2004

Structured Adjustable Rate Mortgage Loan Trust

(Mortgage Pass-Through Certificates, Series 2004-20)

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TABLE OF CONTENTS

PAGE

ARTICLE I

CONVEYANCE OF MORTGAGE LOANS

Section 1.01. Mortgage Loans.......................................3

Section 1.02. Delivery of Documents................................4

Section 1.03. Review of Documentation..............................4

Section 1.04. Representations and Warranties of the Seller.........4

Section 1.05. Grant Clause........................................13

Section 1.06. Assignment by Depositor.............................13

ARTICLE II

MISCELLANEOUS PROVISIONS

Section 2.01. Binding Nature of Agreement; Assignment.............14

Section 2.02. Entire Agreement....................................14

Section 2.03. Amendment...........................................14

Section 2.04. Governing Law.......................................15

Section 2.05. Severability of Provisions..........................15

Section 2.06. Indulgences; No Waivers.............................15

Section 2.07. Headings Not to Affect Interpretation...............15

Section 2.08. Benefits of Agreement...............................15

Section 2.09. Counterparts........................................15

SCHEDULE

SCHEDULE A Mortgage Loan Schedule

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This MORTGAGE LOAN SALE AND ASSIGNMENT AGREEMENT, dated as of December

1, 2004 (the "Agreement"), is executed by and between Lehman Brothers Holdings

Inc. (the "Seller") and Structured Asset Securities Corporation (the

"Depositor").

All capitalized terms not defined herein shall have the same meanings

assigned to such terms in that certain Trust Agreement (the "Trust Agreement"),

dated as of December 1, 2004, among the Depositor, Aurora Loan Services Inc., as

master servicer ("Aurora"), and Wells Fargo Bank, National Association, as

trustee (the "Trustee").

W I T N E S S E T H:

WHEREAS, Lehman Brothers Bank, FSB (the "Bank"), pursuant to the

following specified agreements (each, a "Bank Transfer Agreement" and

collectively, the "Transfer Agreements"), has purchased or received certain

mortgage loans identified on the Mortgage Loan Schedule attached hereto as

Schedule A-1 (each, a "Bank Transferred Mortgage Loan" and collectively, the

"Transferred Mortgage Loans"):

1. Mortgage Loan Purchase and Warranties Agreement, dated as of

August 1, 2002, by and between the Bank and ACT Lending

Corporation ("ACT");

2. Loan Purchase Agreement, dated as of August 29, 2002, by and

between the Bank and American Gold Mortgage Corp. ("American

Gold");

3. Loan Purchase Agreement, dated as of January 24, 2003, by and

between the Bank and American Sterling Bank ("American

Sterling");

4. Flow Seller's Warranties and Servicing Agreement, dated as of

June 1, 2004, by and between the Bank and Countrywide Home

Loans, Inc. ("Countrywide");

5. Loan Purchase Agreement, dated as of February 26, 2002, by and

between the Bank and CTX Mortgage ("CTX");

6. Loan Purchase Agreement, dated as of December 5, 2002, by and

between the Bank and E-Loan Mortgage ("E-Loan");

7. Loan Purchase Agreement, dated as of October 10, 2002, by and

between the Bank and Family Lending Services, Inc. ("Family

Lending");

8. Loan Purchase Agreement, dated as of September 26, 2002, by and

between the Bank and First Financial Equities, Inc. ("First

Financial");

9. Master Mortgage Loan Purchase and Warranties Agreement, dated as

of August 27, 2004, by and between the Bank and First National

Bank of Nevada ("FNBN");

10. Loan Purchase Agreement, dated as of July 28, 2004, by and

between the Bank and Ideal Mortgage Bankers, Ltd dba Lend

America dba Lending Key ("Ideal");

11. Flow Purchase and Warranties Agreement, dated as of February 13,

2001, by and between the Bank and IndyMac Bank, F.S.B.

("IndyMac") and amendments dated as of June 27, 2001, July 19,

2002 and December 1, 2003;

12. Flow Purchase, Warranties and Servicing Agreement, dated as of

July 1, 2003, by and between the Bank and Indymac;

13. Loan Purchase Agreement, dated as of March 15, 2002, by and

between the Bank and Metrociti Mortgage LLC ("Metrociti");

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14. Loan Purchase Agreement, dated as of December 31, 2003, by and

between the Bank and MortgageIT d/b/a MIT Lending ("MIT");

15. Loan Purchase Agreement, dated as of July 2, 2003, by and

between the Bank and Mylor Financial Group, Inc. ("Mylor

Financial");

16. Flow Mortgage Loan Purchase and Warranties Agreement, dated as

of August 1, 2001, by and between the Bank, National Bank of

Commerce ("NBC"), Central California Bank & Trust, NBC Bank,

FSB, First Market Bank and Commerce Finance Company;

17. Flow Purchase and Warranties Agreement, dated as of September

25, 2003, by and between the Bank and Plaza Home Mortgage Inc.

("Plaza Home");

18. Flow Mortgage Loan Purchase and Warranties Agreement, , dated as

of May 10, 2004, by and between the Bank and Quicken Loans Inc.

("Quicken");

19. Loan Purchase Agreement, dated as of September 8, 2003, by and

between the Bank and RBC Mortgage Company ("RBC") and amended as

of May 2004;

20. Loan Purchase Agreement, dated as of April 8, 2004, by and

between the Bank and Reliant Mortgage Company, LLC ("Reliant");

21. Flow Mortgage Loan Purchase and Warranties Agreement, dated as

of June 10, 2002, by and between the Bank and SIB Mortgage Corp.

("SIB"), as amended by Amendment No. 1 dated as of November 1,

2002 and Amendment No. 2 dated as of September 29, 2003;

22. Loan Purchase Agreement, dated as of December 12, 2004, by and

between the Bank and Wall Street Mortgage Bankers ("Wall

Street");

23. Loan Purchase Agreement, dated as of September 2, 2004, by and

between the Bank and Winstar Mortgage Partners ("Winstar" and

collectively with ACT, American Gold, American Sterling,

Countrywide, CTX, E-Loan, Family Lending, First Financial, FNBN,

Ideal, IndyMac, Metrociti, MIT, Mylor Financial, NBC, Plaza

Home, Quicken, RBC, Reliant, SIB and Wall Street, the

"Transferors" and each, a "Transferor").

WHEREAS, in addition to the Bank Transferred Mortgage Loans, the Bank

has funded certain mortgage loans originated by Aurora Loan Services Inc.

identified on the Mortgage Loan Schedule attached hereto as Schedule A-2 (each,

a "Bank Originated Mortgage Loan" and together with the Bank Transferred

Mortgage Loans, the "Bank Mortgage Loans" or the "Mortgage Loans");

WHEREAS, pursuant to an Assignment and Assumption Agreement (the

"Assignment and Assumption Agreement"), dated as of December 1, 2004, between

the Bank, as assignor, and the Seller, as assignee, the Bank has assigned all of

its right, title and interest in and to the Bank Transfer Agreements and related

Mortgage Loans as listed on Schedule A-1, in the case of the Bank Transferred

Mortgage Loans, or Schedule A-2, in the case of the Bank Originated Mortgage

Loans, and the Seller has accepted the rights and benefits of, and assumed the

obligations of the Bank under, the Bank Transfer Agreements;

WHEREAS, the Seller is a party to the following servicing agreements

(collectively, the "Servicing Agreement") pursuant to which the Mortgage Loans

are serviced by Aurora, Colonial Savings, F.A. ("Colonial"), Countrywide and

IndyMac (each as a servicer, a "Servicer" and collectively, the "Servicers"):

1. Servicing Agreement, dated as of December 1, 2004, between the

Seller and Aurora pursuant to which the Mortgage Loans are

serviced by Aurora;

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2. Reconstituted Servicing Agreement, dated as of December 1, 2004,

by and between the Seller and IndyMac;

3. Reconstituted Servicing Agreement, dated as of December 1, 2004,

by and between the Seller and Countrywide; and

5. Correspondent Servicing Agreement, dated as of June 26, 2002, by

and among the Bank, Aurora and Colonial and Transfer Notice,

dated as of December 1, 2004, between the Seller and Colonial.

WHEREAS, the Seller desires to sell, without recourse, all of its

rights, title and interest in and to the Mortgage Loans (exclusive of any

Retained Interest on such Mortgage Loans) to the Depositor and to assign all of

its rights and interest under the Transfer Agreements and the Servicing

Agreements relating to the Mortgage Loans, and to delegate all of its

obligations thereunder, to the Depositor; and

WHEREAS, the Seller and the Depositor acknowledge and agree that the

Depositor will convey the Mortgage Loans to a Trust Fund created pursuant to the

Trust Agreement, assign all of its rights and delegate all of its obligations

hereunder to the Trustee for the benefit of the Certificateholders, and that

each reference herein to the Depositor is intended, unless otherwise specified,

to mean the Depositor or the Trustee, as assignee, whichever is the owner of the

Mortgage Loans from time to time.

NOW, THEREFORE, in consideration of the mutual agreements herein set

forth, and for other good and valuable consideration, the receipt and adequacy

of which are hereby acknowledged, the Seller and the Depositor agree as follows:

ARTICLE I

CONVEYANCE OF MORTGAGE LOANS

Section 1.01. Mortgage Loans.

(a) Sale of Mortgage Loans. Concurrently with the execution and

delivery of this Agreement, the Seller does hereby transfer, assign, set over,

deposit with and otherwise convey to the Depositor, without recourse, subject to

Sections 1.03 and 1.04, all the right, title and interest of the Seller in and

to the Mortgage Loans (exclusive of any Retained Interest on such Mortgage

Loans, if any) identified on Schedule A-1 and Schedule A-2 hereto, having an

aggregate principal balance as of the Cut-off Date of $926,474,085.46. Such

conveyance includes, without limitation, the right to all distributions of

principal and interest received on or with respect to the Mortgage Loans on or

after December 1, 2004 other than (i) any amounts representing Retained

Interest, if any, and (ii) payments of principal and interest due on or before

such date, and all such payments due after such date but received prior to such

date and intended by the related Mortgagors to be applied after such date,

together with all of the Seller's right, title and interest in and to each

related account and all amounts from time to time credited to and the proceeds

of such account, any REO Property and the proceeds thereof, the Seller's rights

under any Insurance Policies relating to the Mortgage Loans, the Seller's

security interest in any collateral pledged to secure the Mortgage Loans,

including the Mortgaged Properties, and any proceeds of the foregoing.

(b) Concurrently with the execution and delivery of this Agreement,

the Seller hereby assigns to the Depositor all of its rights and interest under

each Transfer Agreement and each Servicing Agreement, other than any right to

receive Retained Interest if any, and any servicing rights retained thereunder,

and delegates to the Depositor all of its obligations thereunder, to the extent

relating to the Mortgage Loans. The Seller and the Depositor further agree that

this Agreement incorporates the terms

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and conditions of any assignment and assumption agreement or other assignment

document required to be entered into under any of the Transfer Agreements (any

such document an "Assignment Agreement") and this Agreement constitutes an

Assignment Agreement under such Transfer Agreement, and the Depositor hereby

assumes the obligations of the assignee under each such Assignment Agreement.

Concurrently with the execution hereof, the Depositor tenders the purchase price

of $926,474,085.46. The Depositor hereby accepts such assignment and delegation,

and shall be entitled to exercise all the rights of the Seller under each

Transfer Agreement and each Servicing Agreement, other than any servicing rights

thereunder, as if the Depositor had been a party to each such agreement.

(c) Schedules of Mortgage Loans. The Depositor and the Seller have

agreed upon which of the Mortgage Loans owned by the Seller are to be purchased

by the Depositor pursuant to this Agreement and the Seller will prepare on or

prior to the Closing Date a final schedule describing such Mortgage Loans (the

"Mortgage Loan Schedule"). The Mortgage Loan Schedule shall conform to the

requirements of the Depositor as set forth in this Agreement and to the

definition of "Mortgage Loan Schedule" under the Trust Agreement. The Mortgage

Loan Schedule attached hereto as Schedule A-1 specifies those Mortgage Loans

that are Transferred Mortgage Loans and the Mortgage Loan Schedule attached

hereto as Schedule A-2 specifies those Mortgage Loans that are Bank Originated

Mortgage Loans and which have been assigned by the Bank to the Seller pursuant

to the Assignment and Assumption Agreement.

Section 1.02. Delivery of Documents.

(a) In connection with such transfer and assignment of the Mortgage

Loans hereunder, the Seller, shall, at least three (3) Business Days prior to

the Closing Date, deliver, or cause to be delivered, to the Depositor (or its

designee) the documents or instruments with respect to each Mortgage Loan (each

a "Mortgage File") so transferred and assigned, as specified in the related

Transfer Agreements or Servicing Agreements.

(b) For Mortgage Loans (if any) that have been prepaid in full on or

after the Cut-off Date and prior to the Closing Date, the Seller, in lieu of

delivering the related Mortgage Files, herewith delivers to the Depositor an

Officer's Certificate which shall include a statement to the effect that all

amounts received in connection with such prepayment that are required to be

deposited in the Collection Account maintained by the Master Servicer for such

purpose have been so deposited.

Section 1.03. Review of Documentation. The Depositor, by execution and

delivery hereof, acknowledges receipt of the Mortgage Files pertaining to the

Mortgage Loans listed on the Mortgage Loan Schedule, subject to review thereof

by the custodian, LaSalle Bank National Association and U.S. Bank National

Association, as applicable (each, a "Custodian" and together, the "Custodians"),

for the Depositor. Each Custodian is required to review, within 45 days

following the Closing Date, each applicable Mortgage File. If in the course of

such review the related Custodian identifies any Material Defect, the Seller

shall be obligated to cure such Material Defect or to repurchase the related

Mortgage Loan from the Depositor (or, at the direction of and on behalf of the

Depositor, from the Trust Fund), or to substitute a Qualifying Substitute

Mortgage Loan therefor, in each case to the same extent and in the same manner

as the Depositor is obligated to the Trustee and the Trust Fund under Section

2.02(c) of the Trust Agreement.

Section 1.04. Representations and Warranties of the Seller.

(a) The Seller hereby represents and warrants to the Depositor that

as of the Closing Date:

(i) The Seller is a corporation duly organized, validly

existing and in good standing under the laws governing its creation and

existence and has full corporate power and authority to

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own its property, to carry on its business as presently conducted, and

to enter into and perform its obligations under this Agreement and the

Assignment and Assumption Agreement;

(ii) The execution and delivery by the Seller of this

Agreement and the Assignment and Assumption Agreement have been duly

authorized by all necessary corporate action on the part of the Seller;

neither the execution and delivery of this Agreement or the Assignment

and Assumption Agreement, nor the consummation of the transactions

herein or therein contemplated, nor compliance with the provisions

hereof or thereof, will conflict with or result in a breach of, or

constitute a default under, any of the provisions of any law,

governmental rule, regulation, judgment, decree or order binding on the

Seller or its properties or the certificate of incorporation or bylaws

of the Seller;

(iii) The execution, delivery and performance by the Seller of

this Agreement and the Assignment and Assumption Agreement and the

consummation of the transactions contemplated hereby and thereby do not

require the consent or approval of, the giving of notice to, the

registration with, or the taking of any other action in respect of, any

state, federal or other governmental authority or agency, except such as

has been obtained, given, effected or taken prior to the date hereof;

(iv) Each of this Agreement and the Assignment and Assumption

Agreement has been duly executed and delivered by the Seller and,

assuming due authorization, execution and delivery by the Bank, in the

case of the Assignment and Assumption Agreement, and the Depositor, in

the case of this Agreement, constitutes a valid and binding obligation

of the Seller enforceable against it in accordance with its respective

terms, except as such enforceability may be subject to (A) applicable

bankruptcy and insolvency laws and other similar laws affecting the

enforcement of the rights of creditors generally and (B) general

principles of equity regardless of whether such enforcement is

considered in a proceeding in equity or at law; and

(v) There are no actions, suits or proceedings pending or,

to the knowledge of the Seller, threatened or likely to be asserted

against or affecting the Seller, before or by any court, administrative

agency, arbitrator or governmental body (A) with respect to any of the

transactions contemplated by this Agreement or the Assignment and

Assumption Agreement or (B) with respect to any other matter which in

the judgment of the Seller will be determined adversely to the Seller

and will if determined adversely to the Seller materially and adversely

affect it or its business, assets, operations or condition, financial or

otherwise, or adversely affect its ability to perform its obligations

under this Agreement or the Assignment and Assumption Agreement.

(b) The representations and warranties of each Transferor with

respect to the Transferred Mortgage Loans in the applicable Transfer Agreement

were made as of the date of such Transfer Agreement. To the extent that any

fact, condition or event with respect to a Transferred Mortgage Loan constitutes

a breach of both (i) a representation or warranty of a Transferor under the

applicable Transfer Agreement and (ii) a representation or warranty of the

Seller under this Agreement, the sole right or remedy of the Depositor with

respect to a breach by the Seller of such representation and warranty (other

than a breach by the Seller of the representations and warranties made pursuant

to Sections 1.04(b)(xii), 1.04(b)(xvii), 1.04(b)(xviii), 1.04(b)(xix),

1.04(b)(xx) and (1.04)(b)(xxi)) shall be the right to enforce the obligations of

such Transferor under any applicable representation or warranty made by it. The

representations made by the Seller pursuant to Sections 1.04(b)(xii),

1.04(b)(xvii), 1.04(b)(xviii), 1.04(b)(xix), 1.04(b)(xx) and 1.04(b)(xxi) shall

be direct obligations of the Seller. The Depositor acknowledges and agrees that

the representations and warranties of the Seller in this Section 1.04(b) (other

than the representations and warranties made pursuant to Sections 1.04(b)(xii),

1.04(b)(xvii), 1.04(b)(xviii), 1.04(b)(xix), 1.04(b)(xx) and 1.04(b)(xxi)) are

applicable only to facts, conditions or

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events that do not constitute a breach of any representation or warranty made by

the related Transferor in the applicable Transfer Agreement. The Seller shall

have no obligation or liability with respect to any breach of a representation

or warranty made by it with respect to the Transferred Mortgage Loans if the

fact, condition or event constituting such breach also constitutes a breach of a

representation or warranty made by the related Transferor in such Transfer

Agreement, without regard to whether the related Transferor fulfills its

contractual obligations in respect of such representation or warranty; provided,

however, that if the related Transferor fulfills its obligations under the

provisions of such Transfer Agreement by substituting for the affected Mortgage

Loan a mortgage loan which is not a Qualifying Substitute Mortgage Loan, the

Seller shall, in exchange for such substitute mortgage loan, provide the

Depositor (a) with the applicable Purchase Price for the affected Mortgage Loan

or (b) within the two-year period following the Closing Date, with a Qualified

Substitute Mortgage Loan for such affected Transferred Mortgage Loan. Subject to

the foregoing, the Seller represents and warrants upon delivery of the

Transferred Mortgage Loans to the Depositor hereunder on the Closing Date, as to

each, that:

(i) The information set forth with respect to the

Transferred Mortgage Loans on the Mortgage Loan Schedule provides an

accurate listing of the Transferred Mortgage Loans, and the information

with respect to each Transferred Mortgage Loan on the Mortgage Loan

Schedule is true and correct in all material respects at the date or

dates respecting which such information is given;

(ii) There are no defaults (other than delinquency in

payment) in complying with the terms of any Mortgage, and the Seller has

no notice as to any taxes, governmental assessments, insurance premiums,

water, sewer and municipal charges, leasehold payments or ground rents

which previously became due and owing but which have not been paid;

(iii) Except in the case of Cooperative Loans, if any, each

Mortgage requires all buildings or other improvements on the related

Mortgaged Property to be insured by a generally acceptable insurer

against loss by fire, hazards of extended coverage and such other

hazards as are customary in the area where the related Mortgaged

Property is located pursuant to insurance policies conforming to the

requirements of the guidelines of FNMA or FHLMC. If upon origination of

the Transferred Mortgage Loan, the Mortgaged Property was in an area

identified in the Federal Register by the Federal Emergency Management

Agency as having special flood hazards (and such flood insurance has

been made available) a flood insurance policy meeting the requirements

of the current guidelines of the Federal Flood Insurance Administration

is in effect which policy conforms to the requirements of the current

guidelines of the Federal Flood Insurance Administration. Each Mortgage

obligates the related Mortgagor thereunder to maintain the hazard

insurance policy at the Mortgagor's cost and expense, and on the

Mortgagor