Crystal Structure of the CheA Histidine Phosphotransfer Domain that Mediates Response Regulator Phosphorylation in Bacterial Chemotaxis
The x-ray crystal structure of the P1 or H domain of the Salmonella CheA protein has been solved at 2.1-Ã resolution. The structure is composed of an up-down up-down four-helix bundle that is typical of histidine phosphotransfer or HPt domains such as Escherichia coli ArcB C and Saccharomyces cerev...
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Veröffentlicht in: | The Journal of biological chemistry 2001-08, Vol.276 (33), p.31074-31082 |
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Sprache: | eng |
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Zusammenfassung: | The x-ray crystal structure of the P1 or H domain of the Salmonella CheA protein has been solved at 2.1-Ã
resolution. The structure is composed of an up-down up-down four-helix bundle that
is typical of histidine phosphotransfer or HPt domains such as Escherichia coli ArcB C and Saccharomyces cerevisiae Ypd1. Loop regions and additional structural features distinguish all three proteins. The CheA domain has an additional C-terminal
helix that lies over the surface formed by the C and D helices. The phosphoaccepting His-48 is located at a solvent-exposed
position in the middle of the B helix where it is surrounded by several residues that are characteristic of other HPt domains.
Mutagenesis studies indicate that conserved glutamate and lysine residues that are part of a hydrogen-bond network with His-48
are essential for the ATP-dependent phosphorylation reaction but not for the phosphotransfer reaction with CheY. These results
suggest that the CheA-P1 domain may serve as a good model for understanding the general function of HPt domains in complex
two-component phosphorelay systems. |
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ISSN: | 0021-9258 1083-351X |
DOI: | 10.1074/jbc.M101943200 |