Nature Structural & Molecular Biology 13, 400 - 407 (2006)
Published online: 23 April 2006; | doi:10.1038/nsmb1085
Reconstruction of the chemotaxis receptor–kinase assemblySang-Youn Park1, Peter P Borbat1, 2, Gabriela Gonzalez-Bonet1, Jaya Bhatnagar1, Abiola M Pollard1, Jack H Freed1, 2, Alexandrine M Bilwes1
& Brian R Crane11
Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York, 14853 USA. 2
The Advanced ESR Technology Center, Cornell University, Ithaca, New York, 14853 USA.
Correspondence should be addressed to Brian R Crane bc69@cornell.edu In bacterial chemotaxis, an assembly of transmembrane receptors, the CheA histidine kinase and the adaptor protein CheW processes environmental stimuli to regulate motility. The structure of a Thermotoga maritima receptor cytoplasmic domain defines CheA interaction regions and metal ion–coordinating charge centers that undergo chemical modification to tune receptor response. Dimeric CheA–CheW, defined by crystallography and pulsed ESR, positions two CheWs to form a cleft that is lined with residues important for receptor interactions and sized to clamp one receptor dimer. CheW residues involved in kinase activation map to interfaces that orient the CheW clamps. CheA regulatory domains associate in crystals through conserved hydrophobic surfaces. Such CheA self-contacts align the CheW receptor clamps for binding receptor tips. Linking layers of ternary complexes with close-packed receptors generates a lattice with reasonable component ratios, cooperative interactions among receptors and accessible sites for modification enzymes.
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