AMENDED AND RESTATED MEZZANINE PROMISSORY NOTE A-1

Exhibit 10.6

AMENDED AND RESTATED MEZZANINE PROMISSORY NOTE A-1

FOR VALUE RECEIVED, each of the entities listed as a “Maker” on the signature pages to this Note (collectively, the “ Maker ”), promises to pay to the order of GOLDMAN SACHS MORTGAGE COMPANY, a New York limited partnership (together with its successors and assigns, “ Holder ”) or to such other account pursuant to such other wiring instruction as the Holder may from time to time designate in writing, the original principal amount of TWO EIGHTY ONE MILLION TWO HUNDRED FIFTY THOUSAND DOLLARS ($281,250,000), or so much thereof as may be outstanding from time to time (the “ Principal Amount ”), together with interest thereon and all other amounts payable to the Holder under the Loan Documents with respect to the Loan, such principal, interest and other amounts to be payable as provided in the Loan Agreement (as defined below) and the other Loan Documents. Capitalized terms used herein but not otherwise defined herein shall have the meanings assigned to such terms in the Loan Agreement.

This Amended and Restated Mezzanine Promissory Note A-1 (this “ Note ”), together with that certain Amended and Restated Mezzanine Promissory Note A-2 (the “ Related Note ”), dated as of April 1, 2008, and effective as of the date hereof, by Maker for the benefit of Citicorp North America, Inc. (“ Citicorp ”), replaces, but does not extinguish the indebtedness evidenced by: (i) that certain Mezzanine Promissory Note A-1 by Maker for the benefit of Goldman Sachs Commercial Mortgage Capital, L.P., (ii) that certain Mezzanine Promissory Note A-2 by Maker for the benefit of Citicorp and (iii) that certain Mezzanine Promissory Note A-3 by Maker for the benefit of SL Green Realty Corp., each dated as of April 1, 2008 (collectively, the “ Original Notes ”). This Note, together with the Related Note, amends and restates the Original Notes in their entirety but does not constitute a novation thereof.

This Note is one of the Notes referred to in that certain Amended and Restated Senior Mezzanine Loan Agreement, dated as of April 1, 2008, between the Maker, as borrower, and the Holder, as a lender (as amended, modified or supplemented and in effect from time to time, the “ Loan Agreement ”) and evidences a portion of the Loan made by the Lender thereunder. Reference to the Loan Agreement is hereby made for a statement of the rights of the Holder and the duties and obligations of the Maker, but neither this reference to the Loan Agreement nor any provision thereof shall affect or impair the absolute and unconditional obligation of the Maker to pay the principal, interest and other amounts payable with respect to this Note when due. The Principal Amount shall bear interest at the rates provided for in the Loan Agreement.

This Note is secured by the Pledge Agreement and the other security interests and liens granted in the Loan Agreement and in other Loan Documents.

The principal sum evidenced by this Note, together with accrued interest and other sums or amounts due hereunder, shall become immediately due and payable at the option of the Holder upon the occurrence and during the continuation of any Event of Default in accordance with the provisions of the Loan Agreement.

With respect to the amounts due and payable pursuant to this Note, the Maker waives demand, presentment and notice, except for notices required by the Loan Documents.

In no event shall the amount of interest (and any other sums or amounts that are deemed to constitute interest under applicable Legal Requirements) due or payable hereunder (including interest calculated at the Default Rate) exceed the maximum rate of interest designated by applicable Legal Requirements (the “ Maximum Amount ”), and in the event such excess payment is inadvertently paid by the Maker or inadvertently received by the Holder, then such excess sum shall be credited as a payment of principal on this Note, and if in excess of the outstanding Principal Amount of this Note, shall be immediately returned to the Maker upon such determination. It is the express intent hereof that the Maker not pay and the Holder not receive, directly or indirectly, interest in excess of the Maximum Amount.

Other than as expressly set forth in the Loan Documents, this Note may not be assigned in whole or in part by the Maker. The Holder shall have the right from time to time at its discretion to assign this Note, in whole or in part, only by registration of such assignment on a register maintained as provided in the Loan Agreement. Maker’s obligations in connection with any such assignment shall be as set forth in the Loan Documents.

The Holder shall not by any act, delay, omission or otherwise be deemed to have amended, modified, supplemented, waived, extended, discharged or term