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Published March 6, 2012 | Published + Supplemental Material
Journal Article Open

Bacterial chemoreceptor arrays are hexagonally packed trimers of receptor dimers networked by rings of kinase and coupling proteins

Abstract

Chemoreceptor arrays are supramolecular transmembrane machines of unknown structure that allow bacteria to sense their surroundings and respond by chemotaxis. We have combined X-ray crystallography of purified proteins with electron cryotomography of native arrays inside cells to reveal the arrangement of the component transmembrane receptors, histidine kinases (CheA) and CheW coupling proteins. Trimers of receptor dimers lie at the vertices of a hexagonal lattice in a "two-facing-two" configuration surrounding a ring of alternating CheA regulatory domains (P5) and CheW couplers. Whereas the CheA kinase domains (P4) project downward below the ring, the CheA dimerization domains (P3) link neighboring rings to form an extended, stable array. This highly interconnected protein architecture underlies the remarkable sensitivity and cooperative nature of transmembrane signaling in bacterial chemotaxis.

Additional Information

© 2012 National Academy of Sciences. Edited by Laura L. Kiessling, University of Wisconsin, Madison, WI, and approved January 13, 2012 (received for review September 23, 2011). Author contributions: A.B., X.L., G.J.J., and B.R.C. designed research; A.B. and X.L. performed research; K.T.H. contributed new reagents/analytic tools; A.B., X.L., A.M.B., and B.R.C. analyzed data; and A.B., X.L., A.M.B., G.J.J., and B.R.C. wrote the paper. The authors declare no conflict of interest. We thank Drs. Morgan Beeby and Songye Chen for collecting some of the tomographic data, Dr. John Heumann for help using the PEET software, Dr. Stanley Maloy for suggesting FtsZ overexpression for minicell production, and A. Vu and Dr. F.W. Dahlquist for advice on choosing constructs for crystallization. We also thank the Cornell High Energy Synchrotron Source for access to data collection facilities. This work was supported by the Howard Hughes Medical Institute, by gifts to Caltech from The Gordon and Betty Moore Foundation, and by National Institutes of Health Grant GM066775 (to B.R.C.).

Attached Files

Published - Briegel2012p17515P_Natl_Acad_Sci_Usa.pdf

Supplemental Material - SM01.mov

Supplemental Material - pnas.1115719109_SI.pdf

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August 19, 2023
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