AMENDMENT
      NUMBER 1 TO TRUST AGREEMENT

    LEHMAN
      XS TRUST, SERIES 2007-4N

    


    This
      is
      Amendment Number 1, dated as of December 1, 2007 and effective as of December
      27, 2007 (this “Amendment”), to the Trust Agreement, dated as of March 1, 2007
      (the “Agreement”), by and among STRUCTURED ASSET SECURITIES CORPORATION., a
      Delaware corporation, as depositor (the “Depositor”), AURORA LOAN SERVICES LLC,
      as master servicer (the “Master Servicer”), and U.S. BANK NATIONAL ASSOCIATION,
      a national banking association, as trustee (the “Trustee”), relating to the
      Lehman XS Trust Mortgage Pass-Through Certificates, Series 2007-4N.

    


    WHEREAS,
      Section 11.03 of the Agreement provides that under the circumstances and subject
      to the conditions set forth therein, the Agreement may be amended from time
      to
      time; 

    


    THEREFORE,
      in accordance therewith and in consideration of the mutual agreements herein
      contained, each party hereto agrees to amend the Agreement to the extent and
      on
      the terms set forth herein for the benefit of the other parties and of the
      Certificateholders.

    


    ARTICLE
      I

    


    DEFINITIONS

    


    SECTION
      1.01. Cross
      Reference to Definitions in Agreement.
      Capitalized terms used in this Amendment and not defined herein or amended
      by
      the terms of this Amendment shall have the meaning assigned to such terms in
      the
      Agreement.

    


    ARTICLE
      II

    


    EFFECTIVENESS

    


    SECTION
      2.01. Section 11.03 of the Agreement provides that the Agreement may be amended
      from time to time by the Depositor, the Master Servicer, the NIMS Insurer and
      the Trustee, with the consent of the Holders of not less than 66 2/3% of the
      Class Principal Amount (or Class Notional Amount or Percentage Interest) of
      each
      Class of Certificates (other than the Grantor Trust Certificates) affected
      thereby, for the purpose of adding any provisions to or changing in any manner
      or eliminating any of the provisions of the Agreement or of modifying in any
      manner the rights of the Holders. Section 11.03 of the Agreement further
      provides that (i) no such amendment shall, as evidenced by an Opinion of
      Counsel, result in an Adverse REMIC Event and (ii) that no such amendment shall
      (a) reduce in any manner the amount of, or delay the timing of, payments
      received on Mortgage Loans which are required to be distributed on any
      Certificate, without the consent of the Holder of such Certificate or (b) reduce
      the aforesaid percentages of Class Principal Amount (or Percentage Interest)
      of
      Certificates of each Class, the Holders of which are required to consent to
      any
      such amendment without the consent of the Holders of 100% of the Class Principal
      Amount or Class Notional Amount (or Percentage Interest) of each Class of
      Certificates affected thereby. 

    
      
         

      

      
         

        
          

        

      

      
         

      

    

    


    SECTION
      2.02. By their execution of this Amendment, the Depositor, the Master Servicer
      and the Trustee evidence their desire to make the amendments to the Agreement
      set forth below.

    


    ARTICLE
      III

    


    AMENDMENTS
      TO THE AGREEMENT

    


    SECTION
      3.01. Amendments.
      

    


    (a) The
      table
      on page 9 is hereby amended by deleting the following row from such
      table:

     

    
      	
              Class
                3-AP

            	
              (33)

            	
              $100

            	
              $10

            


    

     

    (b) Footnote
      18 on page 11 is hereby amended by adding the following sentence to the end
      of
      such footnote:

    


    “In
      addition, 100% of Prepayment Premiums from each Pool 3 Mortgage Loan (except
      for
      Prepayment Premiums with respect to the Pool 3 Mortgage Loans serviced by
      Countrywide Servicing, which will be retained by Countrywide Servicing) will
      be
      distributed to the Class 3-AX Certificates.” 

    


    (c) Footnote
      33 on page 13 is hereby amended by deleting the last sentence of such
      footnote.

    


    (d) Section
      1.01 is hereby amended by deleting references to “Class 3-AP” in the definitions
      of “Privately Offered Certificates” and “Voting Interests.”

    


    (e) Section
      1.01 is hereby amended by changing “88%” to “89%” in the definition of “Voting
      Interests.”

    


    (f) Section
      4.03(a)(iii) is hereby amended by deleting the reference to “Class 3-AP.”


    


    (g) Section
      5.02(f) is hereby amended by replacing the last sentence of such section with
      the following:

    


    “On
      each
      Distribution Date, the Paying Agent shall distribute to the Holders of the
      Class
      3-AX Certificates, any Prepayment Premiums paid by borrowers upon voluntary
      full
      or partial prepayment of the Mortgage Loans in Pool 3 (except for Prepayment
      Premiums with respect to the Pool 3 Mortgage Loans serviced by Countrywide
      Servicing, which will be retained by Countrywide Servicing).” 

    


    (h) Section
      5.07(c) is hereby amended by deleting the last sentence of such section and
      replacing it with the following:

    
      
         

      

      
        2

        
          

        

      

      
         

      

    

    


    “On
      the
      Distribution Date in January 2008, the Trustee shall distribute $100 from the
      Class 3-AP Reserve Fund to the Holders of the Class 3-AX
      Certificates.”

    


    (i) Section
      10.01(l) is hereby amended by replacing the last paragraph of such section
      with
      the following:

    


    “It
      is
      the intention of the parties hereto that the segregated pool of assets
      consisting of any collections of Prepayment Premiums related to the Mortgage
      Loans in Pool 3 and the related Class P Reserve Fund distributable to the Class
      3-AX Certificates shall constitute a grantor trust for federal income tax
      purposes. The Trustee, by its execution and delivery hereof, acknowledges the
      assignment to it of the rights to receive such Prepayment Premiums and declares
      that it holds and will hold such assets in trust for the exclusive use and
      benefit of all present and future Holders of the Class 3-AX Certificates. The
      rights of Holders of the Class 3-AX Certificates to receive distributions from
      the proceeds of such Prepayment Premiums, and all ownership interests of such
      Holders in and to such distributions, shall be as set forth in this Agreement.”


    


    (j) Upon
      the
      effective date of this Amendment, the Class 3-AP Certificates shall be
      retired.

    


    ARTICLE
      IV

    


    MISCELLANEOUS

    


    SECTION
      4.01. Counterparts.
      This
      Amendment may be executed in two or more counterparts (and by different parties
      on separate counterparts), each of which shall be an original, but all of which
      together shall constitute one and the same instrument.

    


    SECTION
      4.02. Headings.
      The
      headings herein are for purposes of reference only and shall not otherwise
      affect the meaning or interpretation or any provision hereof.

    


    SECTION
      4.03. Agreement
      in Full Force and Effect as Amended.
      Except
      as specifically amended or waived hereby, all of the terms and conditions of
      the
      Agreement shall remain in full force and effect. All references to the Agreement
      in any other document or instrument shall be deemed to mean such Agreement
      as
      amended by this Amendment. This Amendment shall not constitute a novation of
      the
      Agreement, but shall constitute an amendment thereof. The parties hereto agree
      to be bound by the terms and obligations of the Agreement, as amended by this
      Amendment, as though the terms and obligations of the Agreement were set forth
      herein.

    


    SECTION
      4.04 Conditions
      to Effectiveness.
      This
      Amendment shall become effective upon the receipt by the Trustee of the opinion
      of counsel referred to in Section 11.03 of the Agreement.

    


    SECTION
      4.05. Governing
      Law.
      THIS
      AMENDMENT SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE LAWS OF
      THE
      STATE OF NEW YORK, WITHOUT REFERENCE TO ITS CONFLICTS OF LAW
      PROVISIONS.

    


    [SIGNATURE
      PAGE IMMEDIATELY FOLLOWS]


    
      
         

      

      
        3

        
          

        

      

      
         

      

    



    IN
      WITNESS WHEREOF, the Depositor, the Trustee and the Master Servicer have caused
      their names to be signed hereto by their respective officers hereunto duly
      authorized as of the day and year first above written.

     

    STRUCTURED
      ASSET SECURITIES 
CORPORATION, as Depositor

    


    


    By:  _____________________________
Name:
      Michael C. Hitzmann
Title:
      Senior Vice President

     

     

    U.S.
      BANK
      NATIONAL ASSOCIATION,
not
      in
      its individual capacity, but solely
as
      Trustee

     

     

    By:  _____________________________
Name:
Title:

     

     

    AURORA
      LOAN SERVICES LLC, 
as
      Master
      Servicer

     

     

    By:  ______________________________
Name:
      Michele Olds
Title:
      Vice President