Characterization of a flavocytochrome that is induced during the anaerobic respiration of Fe3+ by Shewanella frigidimarina NCIMB400.

摘要: A 63.9 kDa periplasmic tetrahaem flavocytochrome c(3), designated Ifc(3), was found to be expressed in Shewanella frigidimarina NCIMB400 grown anaerobically with ferric citrate or pyrophosphate as the sole terminal electron acceptor, but not anaerobic cultures of bacterium other respiratory substrates. Ifc(3) purified homogeneity and revealed by biochemical, spectroscopic primary structure analyses contain four low-spin bis-His-ligated c(3)-haems, midpoint reduction potentials -73, -141, -174 -259 mV. low-potential flavin present form non-covalently bound FAD; protein possessed a unidirectional fumarate reductase activity. Disruption chromosomal gene encoding ifcA, did lead significant change rate Fe(3+) batch culture. However, during such growth Ifc(3)-deficient mutant produced both 35 c-type cytochrome 45 membrane-associated at markedly higher levels than parent strain. Nucleotide sequencing data from directly upstream ifcA indicated presence an open reading frame putative outer-membrane beta-barrel 324 amino acid residues.