QcrCAB operon of a nocardia-form actinomycete Rhodococcus rhodochrous encodes cytochrome reductase complex with diheme cytochrome cc subunit.
Structural genes encoding quinol-cytochrome c reductase (QcR) were cloned and sequenced from nocardia-form actinomycete Rhodococcus rhodochrous. QcrC and qcrA encode diheme cytochrome cc and the Rieske Fe-S protein, respectively, while the qcrB product is a diheme cytochrome b. These amino acid sequences are similar to those of Corynebacterium and Mycobacterium, the members of high G+C content firmicutes. The presence of diheme cytochrome cc subunit as a sole c-type cytochrome in these organisms suggests the direct elecron transfer to cytochrome c oxidase. The N-terminal half of the Rieske Fe-S proteins of these bacteria has a unique structure with three transmembrane helices, while the C-terminal half sequence is conserved. A phylogenetic tree using the latter region showed that high G+C firmicutes form a clear clade with Thermus, but not with low G+C firmicutes.
Sone
Nobuhito
N
Department of Biochemical Engineering and Science, Kyushu Institute of Technology, Kawazu 680-4, Iizuka, Fukuoka-ken 820-8502, Japan. sone@bse.kyutech.ac.jp
Fukuda
Mayo
M
Katayama
Shigetaka
S
Jyoudai
Aki
A
Syugyou
Mie
M
Noguchi
Shunsuke
S
Sakamoto
Junshi
J
D000595:Amino Acid Sequence; D003001:Cloning, Molecular; D003579:Cytochrome Reductases / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics*; D003573:Cytochrome b Group / Q000737:chemistry / Q000235:genetics; D045346:Cytochrome b6f Complex; D003574:Cytochrome c Group / Q000737:chemistry / Q000235:genetics; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D009876:Operon; D010802:Phylogeny; D012240:Rhodococcus / Q000737:chemistry / Q000201:enzymology / Q000235:genetics*; D016415:Sequence Alignment
D003573:Cytochrome b Group; D003574:Cytochrome c Group; D045346:Cytochrome b6f Complex; D003579:Cytochrome Reductases