Send to

Choose Destination
Biochim Biophys Acta. 2003 Mar 6;1557(1-3):125-31.

QcrCAB operon of a nocardia-form actinomycete Rhodococcus rhodochrous encodes cytochrome reductase complex with diheme cytochrome cc subunit.

Author information

Department of Biochemical Engineering and Science, Kyushu Institute of Technology, Kawazu 680-4, Iizuka, Fukuoka-ken 820-8502, Japan.


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.

[Indexed for MEDLINE]
Free full text

Supplemental Content

Full text links

Icon for Elsevier Science
Loading ...
Support Center