The structural gene (fdxA) coding for a 7Fe type ferredoxin of a oxidizing bacterium Bacillus schlegelii has been cloned and thermophilic hydrogen sequenced. The fdxA coding region is 231 nucleotides which codes for a 77 amino acids protein with the molecular weight of 8,744 except for iron-sulfur dusters. The fdxA gene has been expressed in E. coli to obtain the recombinant ferredoxin. The recombinant ferredoxin have shown the identical properties to the native one for absorption spectra, and SDS-PAGE. (C) 1994 Academic Press, Inc.