EXECUTION


     

    


     

    STRUCTURED
      ASSET SECURITIES CORPORATION,

     

    as
      Purchaser

     

    and

     

    THORNBURG
      MORTGAGE FUNDING, INC.,

     

    


     

    as
      Seller

     

    


     

    


     

    SASCO
      MORTGAGE LOAN PURCHASE AGREEMENT

     

    Dated
      as
      of February 1, 2007

     

    (Adjustable
      Rate and Hybrid Mortgage Loans)

     

    Thornburg
      Mortgage Securities Trust 2007-1

    Mortgage-Backed
      Notes, Series 2007-1

     


    
      
         

      

      
         

        
          

        

      

      
         

      

    



    Table
      of Contents

    Page

     

    
      
        	
                ARTICLE
                  I. DEFINITIONS AND SCHEDULES

              	
                2

              
	 	 
	
                Section
                  1.01.

              	
                Definitions

              	
                2

              
	 	 
	
                ARTICLE
                  II. SALE OF MORTGAGE LOANS AND THE CONTRACTUAL RIGHTS; PAYMENT
                  OF PURCHASE
                  PRICE

              	
                2

              
	 	 
	
                Section
                  2.01.

              	
                Sale
                  of Mortgage Loans; Assignment
                  of the Contractual Rights and the TMFI Contractual Rights

              	
                2

              
	
                Section
                  2.02.

              	
                Obligations
                  of the Seller Upon Sale

              	
                2

              
	
                Section
                  2.03.

              	
                Payment
                  of Purchase Price for the Mortgage Loans

              	
                4

              
	 	 
	
                ARTICLE
                  III. REPRESENTATIONS AND WARRANTIES; REMEDIES FOR BREACH

              	
                4

              
	 	 
	
                Section
                  3.01

              	
                Seller
                  Representations and Warranties Relating to the Mortgage
                  Loans

              	
                4

              
	
                Section
                  3.02.

              	
                Seller’s
                  Representations and Warranties

              	
                4

              
	
                Section
                  3.03

              	
                Remedies
                  for Breach of Representations and Warranties

              	
                5

              
	 	 
	
                ARTICLE
                  IV. SELLER’S COVENANTS

              	
                6

              
	 	 
	
                Section
                  4.01.

              	
                Covenants
                  of the Seller

              	
                6

              
	 	 
	
                ARTICLE
                  V. INDEMNIFICATION

              	
                6

              
	 	 
	
                Section
                  5.01.

              	
                Indemnification

              	
                6

              
	 	 
	
                ARTICLE
                  VI. TERMINATION

              	
                6

              
	 	 
	
                Section
                  6.01.

              	
                Termination

              	
                6

              
	 	 
	
                ARTICLE
                  VII. MISCELLANEOUS PROVISIONS

              	
                7

              
	 	 
	
                Section
                  7.01.

              	
                Amendment

              	
                7

              
	
                Section
                  7.02.

              	
                Governing
                  Law

              	
                7

              
	
                Section
                  7.03.

              	
                Notices

              	
                7

              
	
                Section
                  7.04.

              	
                Severability
                  of Provisions

              	
                8

              
	
                Section
                  7.05.

              	
                Counterparts

              	
                8

              
	
                Section
                  7.06.

              	
                Further
                  Agreements

              	
                8

              
	
                Section
                  7.07.

              	
                Intention
                  of the Parties

              	
                8

              
	
                Section
                  7.08.

              	
                Successors
                  and Assigns: Assignment of Purchase Agreement

              	
                8

              


      

    

     

    
      
        	
                Schedule
                  I:

              	
                Mortgage
                  Loan Schedule.

              	
                I-1

              
	
                Schedule
                  II:

              	
                List
                  of Servicers and Servicing Agreements

              	
                II-1

              
	
                Schedule
                  III:

              	
                Seller’s
                  Representations and Warranties Relating to Mortgage Loans.

              	
                III-1

              


      

    

    


     


    
      
         

      

      
        i

        
          

        

      

      
         

      

    


    THIS
      SASCO MORTGAGE LOAN PURCHASE AGREEMENT, dated as of February 1, 2007 (the
“Agreement”),
      is
      made and entered into between Thornburg Mortgage Funding, Inc., a Delaware
      corporation (the “Seller”),
      and
      Structured Asset Securities Corporation, a Delaware corporation (the
“Purchaser”).

     

    W
      I T N E S S E T H

     

    WHEREAS,
      effective with the execution of the TMFI Mortgage Loan Purchase Agreement dated
      as of February 1, 2007 (the “TMFI Purchase Agreement”) between Thornburg
      Mortgage Home Loans, Inc. (the “Initial Seller”) as seller, and the Seller, as
      purchaser, the Seller, as of the Closing Date, is the owner of the notes or
      other evidence of indebtedness (the “Mortgage
      Notes”)
      so
      indicated on Schedule I hereto referred to below, and the other documents or
      instruments constituting the Mortgage File (collectively, the “Mortgage
      Loans”)
      and,
      as a consequence thereof, the Seller owns the mortgages or deeds of trust (the
      “Mortgages”)
      on the
      related properties (the “Mortgaged
      Properties”)
      securing such Mortgage Loans, including rights to (a) any property acquired
      by
      foreclosure or deed in lieu of foreclosure or otherwise, (b) the proceeds of
      any
      insurance policies covering the Mortgage Loans or the Mortgaged Properties
      or
      the obligors on the Mortgage Loans and (c) the Seller’s security interest in any
      Additional Collateral; and

     

    WHEREAS,
      effective with the execution of the TMFI Mortgage Loan Purchase Agreement,
      the
      Initial Seller, as of the Closing Date, has assigned to the Seller all its
      rights and interest under the servicing agreements identified on Schedule II
      hereto (each a “Servicing
      Agreement,”
and
      together the “Servicing
      Agreements”),
      other
      than any servicing rights retained pursuant to the provisions of the Servicing
      Agreements, but only to the extent such rights relate to the servicing of the
      Mortgage Loans (the “Contractual
      Rights”);
      and

     

    WHEREAS,
      the parties hereto desire that the Seller sell the Mortgage Loans, the Mortgages
      and related assets referred to above, assign the Contractual Rights and assign
      its rights with respect to the representations and warranties of the Initial
      Seller and remedies for breach pursuant to the TMFI Purchase Agreement (such
      rights and remedies, the “TMFI
      Contractual Rights”)
      to the
      Purchaser pursuant to the terms of this Agreement; and

     

    WHEREAS,
      the Seller understands that the Purchaser, simultaneously with the execution
      of
      this Agreement, intends to transfer and assign all of its rights, title and
      interests in and to the Mortgage Loans, the Mortgages and the related assets,
      the Contractual Rights and the TMFI Contractual Rights to Thornburg Mortgage
      Securities Trust 2007-1 (the “Trust”)
      pursuant to the terms of that certain Sale and Servicing Agreement (the
“Sale
      and Servicing Agreement”)
      dated as
      of February 1, 2007 by and among the Trust, as issuer (the “Issuer”),
      the
      Purchaser, as depositor (in such capacity, the “Depositor”),
      the
      Seller, the Initial Seller, Wells Fargo Bank, N.A., as master servicer and
      securities administrator, and LaSalle Bank, National Association, as indenture
      trustee (the “Indenture
      Trustee”),
      and
      the Seller has agreed to perform certain obligations under this Agreement to
      accommodate such transfer and assignment; and 

     

    WHEREAS,
      the Issuer intends to pledge the Mortgage Loans, the Mortgages and related
      assets, the Contractual Rights and the TMFI Contractual Rights to the Indenture
      Trustee pursuant to an Indenture dated as of February 1, 2007 (the “Indenture”)
      between the Issuer and the Indenture Trustee, pursuant to which the Issuer
      shall
      issue its Mortgage-Backed Notes, Series 2007-1 (the “Notes”),
      the
      payment of which is to be secured by such pledged assets.

     


    
      
         

      

      
        1

        
          

        

      

      
         

      

    

     

    NOW,
      THEREFORE, in consideration of the mutual covenants herein contained and other
      good and valuable consideration, the receipt and adequacy of which are hereby
      acknowledged, the parties hereto agree as follows:

     

    ARTICLE
      I.

     

    DEFINITIONS
      AND SCHEDULES

     

    Section
      1.01. Definitions. Any
      capitalized term used but not defined herein shall have the meaning assigned
      thereto in the Sale and Servicing Agreement and the Indenture.

     

    ARTICLE
      II.


     

    SALE
      OF
      MORTGAGE LOANS AND THE CONTRACTUAL RIGHTS; 

    PAYMENT
      OF PURCHASE PRICE

     

    Section
      2.01. Sale
      of Mortgage Loans; Assignment of the Contractual Rights and the TMFI Contractual
      Rights. The
      Seller, concurrently with the execution and delivery of this Agreement, does
      hereby sell, assign, set over, and otherwise convey to the Purchaser, without
      recourse, all of its right, title and interest in, to and under (i) each
      Mortgage Loan, including the related Cut-Off Date Principal Balance, and all
      collections in respect of interest and principal due after the Cut-Off Date
      (and
      all principal received before the Cut-Off Date to the extent such principal
      relates to a Monthly Payment due after the Cut-Off Date); (ii) property which
      secured such Mortgage Loan and which has been acquired by foreclosure or deed
      in
      lieu of foreclosure; (iii) its interest in any insurance policies in respect
      of
      the Mortgage Loans; (iv) any Additional Collateral with respect to the Mortgage
      Loans; and (v) all proceeds of any of the foregoing.

     

    Concurrently
      with the execution and delivery of this Agreement, the Seller hereby assigns
      to
      the Purchaser the Contractual Rights and the TMFI Contractual Rights. The
      Purchaser hereby accepts such assignment, and shall be entitled to exercise
      such
      Contractual Rights under each Servicing Agreement and such TMFI Contractual
      Rights as if the Purchaser had been a party to each such Servicing Agreement
      and
      the TMFI Purchase Agreement, respectively.

     

    Section
      2.02. Obligations
      of the Seller Upon Sale and Assignment. In
      connection with the transfer and assignment pursuant to Section 2.01 hereof,
      the
      Seller further agrees, at its own expense, on or prior to the Closing Date,
      (a)
      to indicate in its books and records that the Mortgage Loans have been sold
      to
      the Purchaser pursuant to this Agreement and (b) to deliver to the Purchaser
      and
      the Indenture Trustee, a computer file containing a true and complete list
      of
      all such Mortgage Loans specifying for each such Mortgage Loan, as of the
      Cut-Off Date, (i) its account number and (ii) the Cut-Off Date Principal Balance
      and such file, which forms a part of Schedule A to the Sale and Servicing
      Agreement, shall also be marked as Schedule I to this Agreement and is hereby
      incorporated into and made a part of this Agreement.

     


    
      
         

      

      
        2

        
          

        

      

      
         

      

    

     

    In
      connection with such conveyance by the Seller, the Seller shall on behalf of
      the
      Purchaser and the Issuer cause the Initial Seller to deliver to, and deposit
      with the Indenture Trustee (or its custodian), on or before the Closing Date,
      the documents described in Section 2.01 of the Sale and Servicing Agreement
      including, but not limited to, the Mortgage File, the Servicing Agreements
      and a
      copy of the TMFI Purchase Agreement. In the case of the Mortgage Loans (if
      any)
      that have been prepaid in full after the Cut-off Date and prior to execution
      of
      this Agreement, the Seller, in lieu of causing the Initial Seller to deliver
      the
      related Mortgage Files, shall cause the Initial Seller to deliver to the
      Purchaser an Officer’s Certificate which shall include a statement to the effect
      that all amounts received in connection with such prepayments that are required
      to be deposited in the Collection Account pursuant to Section 2.01 of the Sale
      and Servicing Agreement have been so deposited.

     

    The
      Seller hereby confirms to the Purchaser that it has made the appropriate entries
      in its general accounting records, to indicate that the Mortgage Loans have
      been
      transferred as directed by the Purchaser.

     

    The
      Purchaser hereby acknowledges its acceptance of all rights, title and interests
      in, to and under the Mortgage Loans and other property, the Contractual Rights
      and the TMFI Contractual Rights, now existing or hereafter created, conveyed
      to
      it pursuant to Section 2.01 hereof.

     

    The
      parties hereto intend that the transaction set forth herein be a non-recourse
      sale by the Seller to the Purchaser of all of the Seller’s rights, title and
      interests in, to and under the Mortgage Loans and other property described
      in
      Section 2.01. Nonetheless, in the event the transaction set forth herein is
      deemed not to be a sale, the Seller hereby grants to the Purchaser a security
      interest in all of the Seller’s rights, title and interests in, to and under the
      Mortgage Loans and other property described in Section 2.01, whether now
      existing or hereafter created, to secure all of the Seller’s obligations
      hereunder; and this Agreement shall constitute a security agreement under
      applicable law. The Seller and the Purchaser shall, to the extent consistent
      with this Agreement, take such actions as may be necessary to ensure that,
      if
      this Agreement were deemed to create a security interest in the Mortgage Loans,
      the Contractual Rights and the TMFI Contractual Rights, such security interest
      would be deemed to be a perfected security interest of first priority under
      applicable law and will be maintained as such throughout the term of the
      Indenture.

     


    
      
         

      

      
        3

        
          

        

      

      
         

      

    

     

    Section
      2.03. Payment
      of Purchase Price for the Mortgage Loans. In
      consideration of the sale of the Mortgage Loans, the related assets, the
      Contractual Rights and the TMFI Contractual Rights from the Seller to the
      Purchaser on the Closing Date, the Purchaser agrees to pay to the Seller on
      the
      Closing Date by transfer of immediately available funds, an amount equal to
      $1,475,654,383.67 (which amount includes accrued interest) (the “Purchase
      Price”).
      The
      Seller shall pay, and be billed directly for, all reasonable expenses incurred
      by the Purchaser or the Issuer in connection with the issuance of the Notes,
      including, without limitation, printing fees incurred in connection with the
      Preliminary Prospectus Supplement, the Final Prospectus Supplement and the
      Memorandum relating to the Notes, fees and expenses of Purchaser’s counsel, fees
      of the rating agencies requested to rate the Notes, accountant’s fees and
      expenses and the fees and expenses of the Trustee and other out-of-pocket costs,
      if any.

     

    ARTICLE
      III.


     

    REPRESENTATIONS
      AND WARRANTIES; REMEDIES FOR BREACH

     

    Section
      3.01. Representations
      and Warranties Relating to the Mortgage Loans. In
      addition to the assignment of the TMFI Contractual Rights, the Seller hereby
      makes the representations and warranties set forth in Schedule III hereto
      applicable to the Mortgage Loans and by this reference incorporated herein,
      as
      of the Closing Date.

     

    Section
      3.02.  Seller’s
      Representations and Warranties. The
      Seller represents, warrants and covenants to the Purchaser as of the Closing
      Date or as of such other date specifically provided herein:

     

    (i) the
      Seller is duly organized, validly existing and in good standing as a corporation
      under the laws of the State of Delaware and is and will remain in compliance
      with the laws of each state in which any Mortgaged Property is located to the
      extent necessary to fulfill its obligations hereunder;

     

    (ii) the
      Seller has the power and authority to hold each Mortgage Loan, to sell each
      Mortgage Loan, to execute, deliver and perform, and to enter into and
      consummate, all transactions contemplated by this Agreement. The Seller has
      duly
      authorized the execution, delivery and performance of this Agreement, has duly
      executed and delivered this Agreement and this Agreement, assuming due
      authorization, execution and delivery by the Purchaser, constitutes a legal,
      valid and binding obligation of the Seller, enforceable against it in accordance
      with its terms except as the enforceability thereof may be limited by
      bankruptcy, insolvency or reorganization or other similar laws in relation
      to
      the rights of creditors generally;

     

    (iii) the
      execution and delivery of this Agreement by the Seller and the performance
      of
      and compliance with the terms of this Agreement will not violate the Seller’s
      certificate of incorporation or by-laws or constitute a material default under
      or result in a material breach or acceleration of, any material contract,
      agreement or other instrument to which the Seller is a party or which may be
      applicable to the Seller or its assets;

     

    (iv) the
      Seller is not in violation of, and the execution and delivery of this Agreement
      by the Seller and its performance and compliance with the terms of this
      Agreement will not constitute a violation with respect to, any order or decree
      of any court or any order or regulation of any federal, state, municipal or
      governmental agency having jurisdiction over the Seller or its assets, which
      violation might have consequences that would materially and adversely affect
      the
      condition (financial or otherwise) or the operation of the Seller or its assets
      or might have consequences that would materially and adversely affect the
      performance of its obligations and duties hereunder;

     


    
      
         

      

      
        4

        
          

        

      

      
         

      

    

     

    (v) the
      Seller does not believe, nor does it have any reason or cause to believe, that
      it cannot perform each and every covenant contained in this
      Agreement;

     

    (vi) the
      Seller has good, marketable and indefeasible title to the Mortgage Loans, free
      and clear of any and all liens, pledges, charges or security interests of any
      nature encumbering the Mortgage Loans;

     

    (vii) the
      Mortgage Loans are not being transferred by the Seller with any intent to
      hinder, delay or defraud any creditors of the Seller;

     

    (viii) there
      are
      no actions or proceedings against, or investigations known to it of, the Seller
      before any court, administrative or other tribunal (A) that might prohibit
      its
      entering into this Agreement, (B) seeking to prevent the sale of the Mortgage
      Loans or the consummation of the transactions contemplated by this Agreement
      or
      (C) that might prohibit or materially and adversely affect the performance
      by
      the Seller of its obligations under, or validity or enforceability of, this
      Agreement;

     

    (ix) no
      consent, approval, authorization or order of any court or governmental agency
      or
      body is required for the execution, delivery and performance by the Seller
      of,
      or compliance by the Seller with, this Agreement or the consummation of the
      transactions contemplated by this Agreement, except for such consents,
      approvals, authorizations or orders, if any, that have been obtained;
      and

     

    (x) the
      consummation of the transactions contemplated by this Agreement are in the
      ordinary course of business of the Seller, and the transfer, assignment and
      conveyance of the Mortgage Notes and the Mortgages by the Seller pursuant to
      this Agreement are not subject to the bulk transfer or any similar statutory
      provisions.

     

    Section
      3.03. Remedies
      for Breach of Representations and Warranties. 
      It is
      understood and agreed that (i) the representations and warranties set forth
      in
      Sections 3.01 and 3.02 and the provisions of Article V, shall survive the
      purchase of the Mortgage Loans, the Contractual Rights and the TMFI Contractual
      Rights hereunder (and in the case of Section 3.01, shall survive delivery of
      the
      respective Mortgage Files to the Indenture Trustee on behalf of the Purchaser)
      and shall inure to the benefit of the Purchaser and its assigns, notwithstanding
      any restrictive or qualified endorsement on any Mortgage Note or Assignment
      or
      the examination or lack of examination of any Mortgage File and (ii) the
      remedies for the breach of such representations and warranties and for the
      failure to deliver the documents referred to in Section 2.02 hereof shall be
      as
      set forth in Section 2.04 of the Sale and Servicing Agreement.

     


    
      
         

      

      
        5

        
          

        

      

      
         

      

    

     

    ARTICLE
      IV.


     

    SELLER’S
      COVENANTS

     

    Section
      4.01. Covenants
      of the Seller. 
      The
      Seller hereby covenants that, except for the transfer hereunder, it will not
      sell, pledge, assign or transfer to any other Person, or grant, create, incur,
      assume or suffer to exist any Lien on any Mortgage Loan, or any interest
      therein; it will notify the Issuer, as assignee of the Purchaser and the
      Indenture Trustee as an assignee of the Issuer of the existence of any Lien
      on
      any Mortgage Loan immediately upon discovery thereof; and it will defend the
      right, title and interest of the Purchaser and its assigns, in, to and under
      the
      Mortgage Loans, against all claims of third parties claiming through or under
      the Seller; provided,
      however,
      that
      nothing in this Section 4.01 shall prevent or be deemed to prohibit the Seller
      from suffering to exist upon any of the Mortgage Loans any Liens for municipal
      or other local taxes and other governmental charges if such taxes or
      governmental charges shall not at the time be due and payable or if the Seller
      shall currently be contesting the validity thereof in good faith by appropriate
      proceedings and shall have set aside on its books adequate reserves with respect
      thereto.

     

    ARTICLE
      V.


     

    INDEMNIFICATION

     

    Section
      5.01. Indemnification. The
      Seller agrees to indemnify and to hold each of the Purchaser, the Trust and
      the
      Indenture Trustee, each of the officers and directors of each such entity and
      each person or entity who controls each such entity or person harmless against
      any and all claims, losses, penalties, fines, forfeitures, legal fees and
      related costs, judgments, and any other costs, fees and expenses that the
      Purchaser, the Trust, the Indenture Trustee, or any such person or entity may
      sustain in any way related to the failure of the Seller to perform its duties
      in
      compliance with the terms of this Agreement. The Seller shall immediately notify
      the Purchaser, the Trust and the Indenture Trustee if a claim is made under
      this
      provision. The Seller shall assume the defense of any such claim and pay all
      expenses in connection therewith, including reasonable counsel fees, and
      promptly pay, discharge and satisfy any judgment or decree which may be entered
      against the Purchaser, the Trust, the Indenture Trustee or any such person
      or
      entity in respect of such claim.

     

    ARTICLE
      VI.

     

    TERMINATION

     

    Section
      6.01. Termination. 
      The
      respective obligations and responsibilities of the Seller and the Purchaser
      created hereby shall terminate, except for the respective indemnity obligations
      as provided herein, upon the termination of the Sale and Servicing Agreement
      as
      provided in Article X thereof.

     


    
      
         

      

      
        6

        
          

        

      

      
         

      

    


    ARTICLE
      VII.

     

    MISCELLANEOUS
      PROVISIONS

     

    Section
      7.01. Amendment. This
      Agreement may be amended from time to time by the Seller and the Purchaser
      by
      written agreement signed by the parties hereto.

     

    Section
      7.02. Governing
      Law. This
      Agreement shall be governed by and construed in accordance with the laws of
      the
      State of New York, without reference to its conflict of law provisions (other
      than Section 5-1401 of the General Obligations Law), and the obligations, rights
      and remedies of the parties hereunder shall be determined in accordance with
      such laws.

     

    Section
      7.03. Notices. 
      All
      demands, notices and communications hereunder shall be in writing and shall
      be
      deemed to have been duly given if personally delivered at or mailed by
      registered mail, postage prepaid, addressed as follows:

     

    if
      to the
      Seller:

     

    Thornburg
      Mortgage Funding, Inc.

    150
      Washington Avenue, Suite 302

    Santa
      Fe,
      New Mexico 87501

    Attention:
      Deborah Burns

    


    or
      such
      other address as may hereafter be furnished to the Purchaser, the Issuer and
      the
      Indenture Trustee in writing by the Seller.

     

    if
      to the
      Purchaser:

     

    Structured
      Asset Securities Corporation

    745
      Seventh Avenue, 7th
      Floor


    New
      York,
      New York 10019

    Attention:
      Legal Department (Thornburg 2007-1)

     

    or
      such
      other address as may hereafter be furnished to the Seller, the Issuer and the
      Indenture Trustee in writing by the Purchaser.

     

    if
      to the
      Issuer:

     

    Thornburg
      Mortgage Securities Trust 2007-1

    c/o
      Wilmington Trust Company 

    1100
      North Market Street

    Wilmington,
      Delaware 19801

    Attention:
      Corporate Trust Administrator (Thornburg 2007-1)

     

    or
      such
      other address as may hereafter be furnished to the Purchaser, the Indenture
      Trustee and the Seller in writing by the Issuer.

     


    
      
         

      

      
        7

        
          

        

      

      
         

      

    

     

    If
      to the
      Indenture Trustee, its Corporate Trust Office:

     

    or
      such
      other address as may hereafter be furnished to the Seller, the Issuer and the
      Purchaser in writing by the Indenture Trustee.

     

    Section
      7.04. Severability
      of Provisions. 
      If any
      one or more of the covenants, agreements, provisions or terms of this Agreement
      shall be held invalid for any reason whatsoever, then such covenants,
      agreements, provisions or terms shall be deemed severable from the remaining
      covenants, agreements, provisions or terms of this Agreement and shall in no
      way
      affect the validity of enforceability of the other provisions of this
      Agreement.

     

    Section
      7.05. Counterparts. 
      This
      Agreement may be executed in one or more counterparts and by the different
      parties hereto on separate counterparts, which may be transmitted by telecopier
      each of which, when so executed, shall be deemed to be an original and such
      counterparts, together, shall constitute one and the same
      agreement.

     

    Section
      7.06. Further
      Agreements. 
      Each
      party hereto agrees to execute and deliver to the other such additional
      documents, instruments or agreements as may be necessary or reasonable and
      appropriate to effectuate the purposes of this Agreement or in connection with
      the issuance of the Notes under the Indenture.

     

    Without
      limiting the generality of the foregoing, as a further inducement for the
      Purchaser to purchase the Mortgage Loans from the Seller, the Seller will
      cooperate with the Purchaser in connection with the sale of the Notes. In that
      connection, the Seller will provide to the Purchaser any and all information
      and
      appropriate verification of information, whether through letters of its auditors
      and counsel or otherwise, as the Purchaser shall reasonably request and will
      provide to the Purchaser such additional representations and warranties,
      covenants, opinions of counsel, letters from auditors, and certificates of
      public officials or officers of the Seller as are reasonably required in
      connection with the offering of the Notes.

     

    Section
      7.07. Intention
      of the Parties. It
      is the
      intention of the parties that the Purchaser is purchasing, and the Seller is
      selling, the Mortgage Loans rather than pledging such Mortgage Loans to secure
      a
      loan by the Purchaser to the Seller. Accordingly, the parties hereto each intend
      to treat the transaction as a sale by the Seller, and a purchase by the
      Purchaser, of the Mortgage Loans. The Purchaser will have the right to review
      the Mortgage Loans and the related Mortgage Files to determine the
      characteristics of the Mortgage Loans which will affect the Federal income
      tax
      consequences of owning the Mortgage Loans and the Seller will cooperate with
      all
      reasonable requests made by the Purchaser in the course of such
      review.

     

    Section
      7.08. Successors
      and Assigns: Assignment of Purchase Agreement. 
      This
      Agreement shall bind and inure to the benefit of and be enforceable by the
      Seller and the Purchaser and their respective assigns. The obligations of the
      Seller under this Agreement cannot be assigned or delegated to a third party
      without the consent of the Purchaser which consent shall be at the Purchaser’s
      sole discretion, provided,
      however,
      that the
      Purchaser acknowledges and agrees that the Seller may assign its obligations
      hereunder to any Person into which the Seller is merged or any corporation
      resulting from any merger, conversion or consolidation to which the Seller
      is a
      party or any Person succeeding to the business of the Seller. The parties hereto
      acknowledge that the Purchaser is acquiring the Mortgage Loans, the Contractual
      Rights and the TMFI Contractual Rights for the purpose of selling and assigning
      them to the Issuer which will pledge them to the Indenture Trustee. As an
      inducement to the Purchaser to purchase the Mortgage Loans, the Seller
      acknowledges and consents to the assignment by the Purchaser to the Issuer
      of
      the TMFI Contractual Rights which may be enforced or exercised with the same
      force and effect as if they had been enforced or exercised by the Purchaser
      directly.

     

    


     


    
      
         

      

      
        8

        
          

        

      

      
         

      

    



    IN
      WITNESS WHEREOF, the Seller and the Purchaser have caused their names to be
      signed to this SASCO Mortgage Loan Purchase Agreement by their respective
      officers thereunto duly authorized as of the day and year first above
      written.

     

    STRUCTURED
      ASSET SECURITIES 

    CORPORATION,
      as Purchaser

     

    By:/s/
      Mary
      Stone                                

         
      Name: Mary Stone

         
      Title: Vice President 

     

     

    THORNBURG
      MORTGAGE FUNDING, INC.,

    as
      Seller

    By:/s/
      Nathan
      Fellers                           
  

         
      Name: Nathan Fellers

         
      Title: Senior Vice President

     


    
      
         

      

      
        
        

        
          

        

      

      
         

      

    


    


    
      	
              STATE
                OF NEW YORK

            	
              )

            
	 	
              )ss.:

            
	
              COUNTY
                OF NEW YORK

            	
              )

            


    

     

    On
      the
      ___ day of February, 2007 before me, a Notary Public in and for said State,
      personally appeared _________________, known to me to be a
      ________________________ of STRUCTURED ASSET SECURITIES CORPORATION, the
      corporation that executed the within instrument, and also known to me to be
      the
      person who executed it on behalf of said corporation, and acknowledged to me
      that such corporation executed the within instrument.

     

    IN
      WITNESS WHEREOF, I have hereunto set my hand and affixed my official seal the
      day and year in this certificate first above written.

     

    _______________________

    Notary
      Public

     

    My
      Commission Expires on _______________

     


    
      
         

      

      
        
        

        
          

        

      

      
         

      

    


    


    
      	
              STATE
                OF NEW MEXICO

            	
              )

            
	 	
              )ss.:

            
	
              COUNTY
                OF SANTA FE

            	
              )

            


    

     

    On
      the
      ____ day of February, 2007 before me, a notary public in and for said State,
      personally appeared Nathan Fellers, known to me to be a Senior Vice President
      of
      THORNBURG MORTGAGE FUNDING, INC., a Delaware corporation that executed the
      within instrument, and also known to me to be the person who executed it on
      behalf of said corporation, and acknowledged to me that such corporation
      executed the within instrument.

     

    IN
      WITNESS WHEREOF, I have hereunto set my hand and affixed my official seal the
      day and year in this certificate first above written.

     

    _______________________

    Notary
      Public

    


    My
      Commission Expires ______________________

    


    


     


    
      
         

      

      
        
        

        
          

        

      

      
         

      

    



    SCHEDULE
      I

     

    MORTGAGE
      LOAN SCHEDULE 

     

    [See
      Schedule I of the Sale and Servicing Agreement]

     

     

     

     

     

     

     


    
      
         

      

      
        I-1

        
          

        

      

      
         

      

    



    SCHEDULE
      II

     

    LIST
      OF
      SERVICING AGREEMENTS (TMST 2007-1)

     

    
      	 	
              1.

            	
              (a)
                Servicing Agreement, dated as of March 1, 2002, among Thornburg Mortgage
                Home Loans, Inc. (“Thornburg”), as seller and servicer and Wells Fargo
                Bank N.A. (“Wells Fargo”), as master servicer, as amended by the Amendment
                to Servicing Agreement, dated as of December 1, 2002, and as amended
                by
                the Second Amendment to Servicing Agreement, dated as of January
                1, 2006,
                and (b) the Subservicing Acknowledgement Agreement, dated as of March
                1,
                2002, between Thornburg, as servicer, and Cenlar FSB, as sub-servicer
                (“Cenlar”), as amended by the Amendment to Subservicing Acknowledgement
                Agreement, dated as of December 1, 2002, and by the Second Amendment
                to
                Subservicing Acknowledgement Agreement, dated as of January 1, 2006,
                including the related Transfer Notice, dated February 21, 2007, from
                Thornburg, as seller, to Thornburg, as servicer, and Cenlar, as
                sub-servicer.

            


    

     

    
      	 	
              2.

            	
              Amended
                and Restated Correspondent Loan Purchase Agreement, dated as of March
                25,
                2002, between Thornburg Mortgage Home Loans, Inc. (“Thornburg”) and First
                Republic Bank (“First Republic”), including the related Transfer Notice,
                dated February 21, 2007, from Thornburg to First
                Republic.

            


    

     

    
      	 	
              3.

            	
              Amended
                and Restated Correspondent Loan Purchase Agreement, dated as of March
                27,
                2002, between Thornburg Mortgage Home Loans, Inc., (“Thornburg”) and
                Colonial Savings, F.A. (“Colonial”), including the related Transfer
                Notice, dated February 21, 2007, from Thornburg to
                Colonial.

            


    

     

    
      	 	
              4.

            	
              Correspondent
                Loan Purchase Agreement, dated as of January 31, 2006, between Thornburg
                Mortgage Home Loans, Inc. (“Thornburg”) and Mellon Trust of New England,
                N.A. (“Mellon”), including the related Transfer Notice, dated February 21,
                2007, from Thornburg to Mellon.

            


    

     

    
      	 	
              5.

            	
              Correspondent
                Loan Purchase Agreement, dated as of April 6, 2006, between Thornburg
                Mortgage Home Loans, Inc. (“Thornburg”) and First Horizon Home Loan Corp.
                (“First Horizon”), including the related Transfer Notice, dated February
                21, 2007, from Thornburg to First
                Horizon.

            


    

     

    


     


    
      
         

      

      
        II-1

        
          

        

      

      
         

      

    



    SCHEDULE
      III

     

    SELLER’S
      REPRESENTATIONS AND 

     

    WARRANTIES
      RELATING TO

     

    MORTGAGE
      LOANS

     

    The
      Seller hereby represents and warrants to, and covenants with, the Purchaser
      that, as to each Mortgage Loan, as of the Closing Date:

     

    
      	
              (i)

            	
              The
                Mortgage Loan is not a loan (A) subject to 12 CFR Part 226.31, 12
                CFR Part
                226.32 or 12 CFR Part 226.34 of Regulation Z, the regulation implementing
                TILA, which implements the Home Ownership and Equity Protection Act
                of
                1994, as amended, or any comparable state law (B) a “High Cost Loan” or
                “Covered Loan” as applicable, as such terms are defined in the current
                Standard & Poor’s LEVELS® GLOSSARY classified and/or defined as a
                “high cost” loan or “predatory,” “high cost,” “threshold” or “covered”
                lending under any other state, federal or local law. The Mortgage
                Loan at
                the time it was made otherwise complied in all material respects
                with any
                and all requirements of any federal, state or local law including,
                but not
                limited to, all predatory lending laws, usury, truth in lending,
                real
                estate settlement procedures (including the Real Estate Settlement
                Procedures Act of 1974, as amended), consumer credit protection,
                equal
                credit opportunity or disclosure laws applicable to such Mortgage
                Loan.

            


    

     

    
      	
              (ii)

            	
              (a)
                The information set forth in the final Mortgage Loan Schedule is
                complete,
                true and correct in all material respects and (b) the Mortgage Note
                or an
                affidavit of lost note with respect to each Mortgage Loan has been
                delivered to the Indenture Trustee or its
                designee.

            


    

     

    
      	
              (iii)

            	
              The
                Seller has acquired its ownership of each Mortgage Loan in good faith
                without notice of any adverse claim, and as of the Closing Date,
                the
                Mortgage Note and the Mortgage are not assigned or pledged, and
                immediately prior to the sale of the Mortgage Loan to the Purchaser,
                the
                Seller was the sole owner thereof and with full right to transfer
                and sell
                the Mortgage Loan to the Purchaser free and clear of any encumbrance,
                equity, lien, pledge, charge, claim or security interest and with
                full
                right and authority subject to no interest or participation of, or
                agreement with, any other party, to sell and assign each Mortgage
                Loan
                pursuant to this Agreement.

            


    

     

     

     

    
      
         

      

      
        III-1