Exhibit 4.3-A CERTIFICATE OF TRUST OF MISSISSIPPI POWER CAPITAL TRUST I THIS CERTIFICATE OF TRUST of Mississippi Power Capital Trust I (the "Trust"), dated January 24, 1997, is being duly executed and filed by the undersigned, as trustee of the Trust, to form a business trust under the Delaware Business Trust Act (12 Del. C. Section 3801, et seq.). 1. Name. The name of the business trust being formed hereby is Mississippi Power Capital Trust I. 2. Delaware Trustee. The name and business address of the trustee of the Trust with a principal place of business in the State of Delaware are Bankers Trust (Delaware), 1001 Jefferson Street, Suite 550, Wilmington, Delaware 19801. 3. Effective Date. This Certificate of Trust shall be effective as of its filing. IN WITNESS WHEREOF, the undersigned, being the sole trustee of the Trust, has executed this Certificate of Trust as of the date first above written. BANKERS TRUST (DELAWARE), as Delaware Trustee By: /s/ M. Lisa Wilkins Name: M. Lisa Wilkins Title: Assistant Secretary