MORTGAGE LOAN SALE AND ASSIGNMENT AGREEMENT

EXECUTION

LEHMAN BROTHERS HOLDINGS INC.,

SELLER

and

STRUCTURED ASSET SECURITIES CORPORATION,

PURCHASER

MORTGAGE LOAN SALE AND ASSIGNMENT AGREEMENT

Dated as of November 1, 2005

Structured Asset Securities Corporation 2005-OPT1

(Mortgage Pass-Through Certificates, Series 2005-OPT1)

TABLE OF CONTENTS

Page

ARTICLE I. CONVEYANCE OF MORTGAGE LOANS

Section 1.01.

Sale of Mortgage Loans.

2

Section 1.02.

Delivery of Documents.

3

Section 1.03.

Review of Documentation.

3

Section 1.04.

Representations and Warranties of the Seller.

3

Section 1.05.

Grant Clause.

9

Section 1.06.

Assignment by Depositor.

10

ARTICLE II. MISCELLANEOUS PROVISIONS

Section 2.01.

Binding Nature of Agreement; Assignment.

10

Section 2.02.

Entire Agreement.

10

Section 2.03.

Amendment.

10

Section 2.04.

Valid Assignment.

11

Section 2.05.

Governing Law.

11

Section 2.06.

Severability of Provisions.

11

Section 2.07.

Indulgences; No Waivers.

12

Section 2.08.

Headings Not to Affect Interpretation.

12

Section 2.09.

Benefits of Agreement.

12

Section 2.10.

Counterparts.

12

SCHEDULE A

Mortgage Loan Schedule (including Prepayment Charge Schedule)

SCHEDULE B

Mortgage Loan Schedule for First Payment Default Mortgage Loans

EXHIBIT A

Certain Defined Terms

EXHIBIT B

Form of Terms Letter

This MORTGAGE LOAN SALE AND ASSIGNMENT AGREEMENT dated as of November 1, 2005 (the “Agreement”), is executed by and between Lehman Brothers Holdings Inc. (“Holdings” or the “Seller”) and Structured Asset Securities Corporation (the “Depositor”).

All capitalized terms not defined herein or in Exhibit A attached hereto shall have the same meanings assigned to such terms in that certain trust agreement dated as of November 1, 2005 (the “Trust Agreement”), among the Depositor, Aurora Loan Services LLC, as master servicer (the “Master Servicer”), MortgageRamp, Inc., as credit risk manager and U.S. 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 (A) a seller’s warranties and servicing agreement dated as of November 20, 2003 (the “Transfer Agreement”), by and among the Bank, as purchaser, Option One Mortgage Corporation (“Option One” or the “Transferor”), Option One Owner Trust 2001-1A, Option One Owner Trust 2001-1B, Option One Owner Trust 2001-2, Option One Owner Trust 2002-3, Option One Owner Trust 2003-4 and Option One Owner Trust 2003-5 and (B) (i) a Purchase Price and Terms Letter from the Bank to Option One, dated September 8, 2005 (OOMC 2005-9), (ii) a Purchase Price and Terms Letter from the Bank to Option One, dated September 9, 2005 (OOMC 2005-10) and (iii) a Purchase Price and Terms Letter from the Bank to Option One, dated September 9, 2005 (OOMC 2005-11) (each, a “PPTL”), has purchased or received from Option One certain mortgage loans, each identified on the Mortgage Loan Schedule attached hereto as Schedule A (collectively, the “Mortgage Loans”):

WHEREAS, pursuant to an assignment and assumption agreement dated as of November 1, 2005 (the “Assignment and Assumption Agreement”), between the Bank, as assignor, and Holdings, as assignee, the Bank has assigned all of its right, title and interest in and to the Transfer Agreement, certain of its rights (as described below) under each PPTL and the Mortgage Loans as listed on Schedule A, and Holdings has accepted the rights and benefits of, and assumed the obligations of the Bank under, the Transfer Agreement;

WHEREAS, Holdings is a party to the servicing agreement dated as of November 1, 2005 (the “Servicing Agreement”), among Option One, as servicer (the “Servicer”), the Seller and the Master Servicer, and acknowledged by the Trustee  pursuant to which the Mortgage Loans are serviced by the Servicer;

WHEREAS, the Seller desires to sell, without recourse, all of its rights, title and interest in and to the Mortgage Loans to the Depositor, assign all of its rights and interest under the Transfer Agreement, the PPTLs and the Servicing Agreement relating to the Mortgage Loans referred to above, and 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.

Sale of 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 identified on Schedule A hereto, having an aggregate principal balance of $591,085,736. Such conveyance includes, without limitation, the right to all distributions of principal and interest received on or with respect to the Mortgage Loans on and after the Cut-off Date, other than 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, all Prepayment Charges received on or with respect to the Mortgage Loans on or after the Cut-off 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.

Concurrently with the execution and delivery of this Agreement, the Seller hereby assigns to the Depositor all of its rights and interest under the Transfer Agreement (including the right to enforce Section 7 of each PPTL with respect to the Mortgage Loans listed on Schedule B hereto (the “First Payment Default Mortgage Loans”)) and the Servicing Agreement, other than 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 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 that 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 set forth in that certain Terms Letter dated as of the date hereof, the form of which is attached as Exhibit B hereto (the “Purchase Price”).  The Depositor hereby accepts such assignment and delegation, and shall be entitled to exercise all the rights of the Seller under the Transfer Agreement, the PPTLs and the Servicing Agreement, other than any servicing rights thereunder, as if the Depositor had been a party to each such agreement.

(b)

Schedule 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 is attached hereto as Schedule A.

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 Transfer Agreement or Servicing Agreement.

(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 Wells Fargo Bank, N.A., as the custodian (the “Custodian”) for the Depositor.  The Custodian is required to review, within 45 days following the Closing Date, each Mortgage File. If in the course of such review the 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 own its property, carry on its business as presently conducted and enter into and perform its obligations under the Assignment and Assumption Agreement and this Agreement;

(ii)

the execution and delivery by the Seller of the Assignment and Assumption Agreement and this Agreement have been duly authorized by all necessary corporate action on the part of the Seller; neither the execution and delivery of the Assignment and Assumption Agreement and this Agreement, nor the consummation of the transactions therein or herein contemplated, nor compliance with the provisions thereof or hereof, 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 the Assignment and Assumption Agreement and this Agreement and the consummation of the transactions contemplated thereby and hereby 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 the Assignment and Assumption Agreement and this 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 the Assignment and Assumption Agreement or this 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 the Assignment and Assumption Agreement or this Agreement.

(b)

The representations and warranties of the Transferor with respect to the Mortgage Loans in the Transfer Agreement were made as of the date of the Transfer Agreement.  To the extent that any fact, condition or event with respect to a Mortgage Loan constitutes a breach of both (i) a representation or warranty of the Transferor under the 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 (except in the case of a breach by the Seller of the representations made by it pursuant to Sections 1.04(b)(xiii) through (xvii)), shall be the right to enforce the obligations of the Transferor under any applicable representation or warranty made by it.  The representations made by the Seller pursuant to Sections 1.04(b)(xiii) through (xvii)) 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) (except in the case of  those representations and warranties made pursuant to Sections 1.04(b)(xiii) through (xvii)) are applicable only to facts, conditions or events that do not constitute a breach of any representation or warranty made by the Transferor in the 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 Mortgage Loans (except in the case of those representations and warranties made by it pursuant to Sections 1.04(b)(xiii) through (xvii)) if the fact, condition or event constituting such breach also constitutes a breach of a representation or warranty made by the Transferor in the Transfer Agreement, without regard to whether the Transferor fulfills its contractual obligations in respect of such representation or warranty; provided, however , that if the Transferor fulfills its obligations under the provisions of the 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 Mortgage Loan.

Subject to the foregoing, the Seller represents and warrants upon delivery of the Mortgage Loans to the Depositor hereunder, as to each, that:

(i)

The information set forth with respect to the Mortgage Loans on the Mortgage Loan Schedule provides an accurate listing of the Mortgage Loans, and the information with respect to each 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 gro