Non-heme iron proteins. The amino acid sequence of rubredoxin from Desulfovibrio vulgaris.

A non-heme iron protein, rubredoxin has been isolated from the sulfate-reducing bacterium, Desulfovibrio vulgaris, strain Hildenborough. The complete amino acid sequence has been established. The 52 amino acid residues of the protein were aligned with the aid of tryptic and chymotryptic peptides and of a fragment produced by cleavage of the Asn-Gly bond (22-23) by hydroxylamine. The sequence of the first 30 residues of the molecule was determined using an automatic sequenator, after removal of the N-terminal methionine by CNBr. In comparing this sequence with those of Micrococcus aerogenes, Clostridium pasteurianum and Peptostreptococcus elsdenii rubredoxins, a high degree of mutation was observed between these homologous proteins. It has been shown that 20 amino acid residues occurred in identical positions. The locations of the four cysteine residues were found to be invariable. A crystallographic study of the Desulfovibrio vulgaris rubredoxin is in progress.