Bacillus subtilis CtaA is a heme-containing membrane protein involved in heme A biosynthesis.
Heme A is a prosthetic group of many respiratory oxidases. It is synthesized from protoheme IX (heme B) seemingly with heme O as a stable intermediate. The Bacillus subtilis ctaA and ctaB genes are required for heme A and heme O synthesis, respectively (B. Svensson, M. Lübben, and L. Hederstedt, Mol. Microbiol. 10:193-201, 1993). Tentatively, CtaA is involved in the monooxygenation and oxidation of the methyl side group on porphyrin ring D in heme A synthesis from heme B. B. subtilis ctaA and ctaB on plasmids in both B. subtilis and Escherichia coli were found to result in a novel membrane-bound heme-containing protein with the characteristics of a low-spin b-type cytochrome. It can be reduced via the respiratory chain, and in the reduced state it shows light absorption maxima at 428, 528, and 558 nm and the alpha-band is split. Purified cytochrome isolated from both B. subtilis and E. coli membranes contained one polypeptide identified as CtaA by amino acid sequence analysis, about 0.2 mol of heme B per mol of polypeptide, and small amounts of heme A.
Svensson
B
B
Department of Microbiology, Lund University, Sweden.
Hederstedt
L
L
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D001412:Bacillus subtilis / Q000737:chemistry* / Q000235:genetics; D001426:Bacterial Proteins; D003573:Cytochrome b Group / Q000737:chemistry / Q000235:genetics*; D004926:Escherichia coli / Q000235:genetics; D005798:Genes, Bacterial / Q000235:genetics*; D006418:Heme / Q000031:analogs & derivatives* / Q000096:biosynthesis; D006420:Hemeproteins / Q000737:chemistry* / Q000235:genetics; D008565:Membrane Proteins / Q000737:chemistry* / Q000235:genetics*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D010957:Plasmids / Q000235:genetics; D017433:Protein Structure, Secondary; D011994:Recombinant Proteins / Q000737:chemistry; D017421:Sequence Analysis; D013053:Spectrophotometry
D000596:Amino Acids; D001426:Bacterial Proteins; C090098:CtaA protein, bacteria; D003573:Cytochrome b Group; D006420:Hemeproteins; D008565:Membrane Proteins; D011994:Recombinant Proteins; C027728:heme a; D006418:Heme