†Present address: Microbiology and Molecular Genetics, University of Texas Medical School, 6431 Fannin, Houston, TX 7730, USA.
Targeting of the chemotaxis methylesterase/deamidase CheB to the polar receptor–kinase cluster in an Escherichia coli cell
Article first published online: 1 JUL 2004
Volume 53, Issue 4, pages 1051–1063, August 2004
How to Cite
Banno, S., Shiomi, D., Homma, M. and Kawagishi, I. (2004), Targeting of the chemotaxis methylesterase/deamidase CheB to the polar receptor–kinase cluster in an Escherichia coli cell. Molecular Microbiology, 53: 1051–1063. doi: 10.1111/j.1365-2958.2004.04176.x
- Issue published online: 1 JUL 2004
- Article first published online: 1 JUL 2004
- Accepted 14 April, 2004.
Chemotactic adaptation to persisting stimulation involves reversible methylation of the chemoreceptors that form complexes with the histidine kinase CheA at a cell pole. The methyltransferase CheR targets to the C-terminal NWETF sequence of the chemoreceptor. In contrast, localization of the methylesterase CheB is largely unknown, although regulation of its activity via phosphorylation is central to adaptation. In this study, green fluorescent protein was fused to full-length CheB or its various parts: the N-terminal regulatory domain (N), the C-terminal catalytic domain (C) and the linker (L). The full-length and NL fusions and, to a lesser extent, the LC fusion localized to a pole. Deletion of the P2 domain from CheA abolished polar localization of the full-length and NL fusions, but did not affect that of the LC fusion. Pull-down assays demonstrated that the NL fragment, but not the LC fragment, binds to the P2 fragment of CheA. These results indicate that binding of the NL domain to the P2 domain targets CheB to the polar signalling complex. The LC fusion, like the chemoreceptor, partially localized in the absence of CheA, suggesting that the LC domain may interact with its substrate sites, either as part of the protein or as a proteolytic fragment.