The Crystal Structure of Zinc-Containing Ferredoxin from a Thermoacidophilic Archaeon (MOLECULAR BIOLOGY AND INFORMATION-Biopolymer Structure)

Abstract

The crystal structure of ferredoxin from thermoacidophilic archaeon Sulfolobus sp. strain 7 was determined by X-ray diffraction analysis at 2.0 A resolution. The structure of the archaeal ferredoxin consists of two parts: core fold part and the N-terminal extension part. The distinct structural feature of this archaeal ferredoxin lies in the zinc-binding center where the zinc ion is tetrahedrally ligated by four amino acid residues. The zinc ion in the zinc-binding center is located at the interface between the core fold and the N-terminal extension, and connects the b-sheet in the N-terminal extension and the central b-sheet in the core fold through the zinc ligation. Thus the zinc ion plays an important role in stabilizing the structure of the present archaeal ferredoxin by connecting the N-terminal extension and the core fold, which may be common to thermoacidophilic archaeal ferredoxins.