Chemotaxis and flagellar genes of Chromobacterium violaceum

Abstract

The availability of the complete genome of the Gram- negative β-proteobacterium Chromobacterium violaceum has increas- ingly impacted our understanding of this microorganism. This review focuses on the genomic organization and structural analysis of the de- duced proteins of the chemosensory adaptation system of C. violaceum. C. violaceum has multiple homologues of most chemotaxis genes, orga- nized mostly in clusters in the bacterial genome. We found at least 67 genes, distributed in 10 gene clusters, involved in the chemotaxis of C. violaceum. A close examination of the chemoreceptors methyl-accept- ing chemotaxis proteins (MCPs), and the deduced sequences of the mem- bers of the two-component signaling system revealed canonical motifs, described as essential for the function of the deduced proteins. The chemoreceptors found in C. violaceum include the complete repertoire of such genes described in bacteria, designated as tsr, tar, trg, and tap; 41 MCP loci were found in the C. violaceum genome. Also, the C. violaceum genome includes a large repertoire of the proteins of the chemosensory transducer system. Multiple homologues of bacterial che- motaxis genes, including CheA, CheB, CheD, CheR, CheV, CheY, CheZ, and CheW, were found in the C. violaceum genome.