6s1k
E. coli Core Signaling Unit, carrying QQQQ receptor mutation
Structural highlights
Function[CHEA_ECOLI] Involved in the transmission of sensory signals from the chemoreceptors to the flagellar motors. CheA is autophosphorylated; it can transfer its phosphate group to either CheB or CheY. [MCP1_ECOLI] Receptor for the attractant L-serine and related amino acids. Is also responsible for chemotaxis away from a wide range of repellents, including leucine, indole, and weak acids. Chemotactic-signal transducers respond to changes in the concentration of attractants and repellents in the environment, transduce a signal from the outside to the inside of the cell, and facilitate sensory adaptation through the variation of the level of methylation. Attractants increase the level of methylation while repellents decrease the level of methylation, the methyl groups are added by the methyltransferase CheR and removed by the methylesterase CheB. Publication Abstract from PubMedTo enable the processing of chemical gradients, chemotactic bacteria possess large arrays of transmembrane chemoreceptors, the histidine kinase CheA, and the adaptor protein CheW, organized as coupled core-signaling units (CSU). Despite decades of study, important questions surrounding the molecular mechanisms of sensory signal transduction remain unresolved, owing especially to the lack of a high-resolution CSU structure. Here, we use cryo-electron tomography and sub-tomogram averaging to determine a structure of the Escherichia coli CSU at sub-nanometer resolution. Based on our experimental data, we use molecular simulations to construct an atomistic model of the CSU, enabling a detailed characterization of CheA conformational dynamics in its native structural context. We identify multiple, distinct conformations of the critical P4 domain as well as asymmetries in the localization of the P3 bundle, offering several novel insights into the CheA signaling mechanism. Structure and dynamics of the E. coli chemotaxis core signaling complex by cryo-electron tomography and molecular simulations.,Cassidy CK, Himes BA, Sun D, Ma J, Zhao G, Parkinson JS, Stansfeld PJ, Luthey-Schulten Z, Zhang P Commun Biol. 2020 Jan 10;3(1):24. doi: 10.1038/s42003-019-0748-0. PMID:31925330[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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