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-A 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.
Mourey
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Groupe de Cristallographie Biologique, Centre National de la Recherche Scientifique/Institut de Pharmacologie et de Biologie Structurale, 205 route de Narbonne, 31077 Toulouse Cedex, France.
Da Re
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S
Pédelacq
J D
JD
Tolstykh
T
T
Faurie
C
C
Guillet
V
V
Stock
J B
JB
Samama
J P
JP
D000255:Adenosine Triphosphate / Q000494:pharmacology; D000595:Amino Acid Sequence; D001426:Bacterial Proteins; D002633:Chemotaxis; D003460:Crystallization; D029968:Escherichia coli Proteins; D006639:Histidine / Q000378:metabolism*; D000071677:Histidine Kinase; D008565:Membrane Proteins / Q000737:chemistry* / Q000502:physiology; D000072236:Methyl-Accepting Chemotaxis Proteins; D008969:Molecular Sequence Data; D010766:Phosphorylation; D013329:Structure-Activity Relationship
D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D008565:Membrane Proteins; D000072236:Methyl-Accepting Chemotaxis Proteins; C000607606:cheY protein, E coli; D006639:Histidine; D000255:Adenosine Triphosphate; D000071677:Histidine Kinase; C000607608:cheA protein, E coli