IDENTIFICATION OF A GENE FOR A RUBRERYTHRIN NIGERYTHRIN-LIKE PROTEIN IN SPIRILLUM VOLUTANS BY USING AMINO-ACID-SEQUENCE DATA FROM MASS-SPECTROMETRY AND NH2-TERMINAL SEQUENCING/

A hydrogen peroxide-resistant mutant of the catalase-negative microaer ophile, Spirillum volutans, constitutively expresses a 21.5 kDa protei n that is undetectable and non-inducible in the wild-type cells. Part of the gene that encodes the protein was cloned using amino acid seque nce data obtained by both mass spectrometry and NH2-terminal sequencin g. The deduced 158 amino acid polypeptide shows high relatedness to ru brerythrin and nigerythrin previously described in the anaerobes Clost ridoium perfringens and Desulfovibrio vulgaris. The protein also shows high similarity to putative rubrerythrin proteins found in the anaero bic archeons Archaeoglobus fulgidus, Methanococcus jannaschii and Meth anobacterium thermoautotrophicum. This is the first report of this typ e of protein in an organism that must respire with oxygen. It seems li kely that the novel combination of methodologies used in this study co uld be applied to the rapid cloning of other genes in bacteria for whi ch no genomic library yet exists.