title: Molecular architecture of chemoreceptor arrays revealed by cryoelectron tomography of Escherichia coli minicells.
abstract: The chemoreceptors of Escherichia coli localize to the cell poles and form a highly ordered array in concert with the CheA kinase and the CheW coupling factor. However, a high-resolution structure of the array has been lacking, and the molecular basis of array assembly has thus remained elusive. Here, we use cryoelectron tomography of flagellated E. coli minicells to derive a 3D map of the intact array. Docking of high-resolution structures into the 3D map provides a model of the core signaling complex, in which a CheA/CheW dimer bridges two adjacent receptor trimers via multiple hydrophobic interactions. A further, hitherto unknown, hydrophobic interaction between CheW and the homologous P5 domain of CheA in an adjacent core complex connects the complexes into an extended array. This architecture provides a structural basis for array formation and could explain the high sensitivity and cooperativity of chemotaxis signaling in E. coli.
authors.affiliation: Department of Pathology and Laboratory Medicine, University of Texas Medical School, Houston, TX 77030, USA. jun.liu.1@uth.tmc.edu
authors.forename: Jun
authors.initials: J
authors.lastname: Liu
authors.forename: Bo
authors.initials: B
authors.lastname: Hu
authors.forename: Dustin R
authors.initials: DR
authors.lastname: Morado
authors.forename: Sneha
authors.initials: S
authors.lastname: Jani
authors.forename: Michael D
authors.initials: MD
authors.lastname: Manson
authors.forename: William
authors.initials: W
authors.lastname: Margolin
mesh_terms: D001426:Bacterial Proteins / Q000648:ultrastructure*; D002633:Chemotaxis / Q000235:genetics*; D020285:Cryoelectron Microscopy / Q000379:methods; D019281:Dimerization; D055032:Electron Microscope Tomography / Q000379:methods; D004926:Escherichia coli / Q000235:genetics*; D029968:Escherichia coli Proteins / Q000648:ultrastructure*; D000071677:Histidine Kinase; D008565:Membrane Proteins / Q000648:ultrastructure*; D000072236:Methyl-Accepting Chemotaxis Proteins; D008958:Models, Molecular; D008968:Molecular Conformation; D015398:Signal Transduction / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; C489103:CheW protein, E coli; D029968:Escherichia coli Proteins; D008565:Membrane Proteins; D000072236:Methyl-Accepting Chemotaxis Proteins; D000071677:Histidine Kinase; C000607608:cheA protein, E coli