Characterization of the gene encoding the [Fe]-hydrogenase from Megasphaera elsdenii

The gene encoding the [Fe]-hydrogenase from the anaerobic bacterium Megasph aera elsdenii has been cloned and sequenced. The gene is monocistronic, in keeping with the protein being a monomer. The translated protein sequence ( 484 residues, M-r = 53 kDa) comprises a small 2[4Fe-4S] ferredoxin-like dom ain and a large domain containing the catalytic site. Comparisons with othe r [Fe]-hydrogenase sequences, including two of which the crystal structures are known, show that the M. elsdenii protein is among the smallest of thes e enzymes and provide useful indications regarding the basic structural cor e common to all [Fe]-hydrogenases. It is, nevertheless, to be noted that th e genome of Thermotoga maritima encodes a putative [Fe]-hydrogenase that wo uld consist of only 301 residues. (C) 2000 Elsevier Science B.V. All rights reserved.