CK Cassidy, Zhuan Qin, Thomas Frosio, Khoosheh Gosink, Zhengyi Yang, Mark Sansom, Phillip Stansfeld, John Parkinson, and Peijun Zhang

The sensory apparatus of the chemotaxis pathway is an array of core-signaling units (CSUs) composed of transmembrane chemoreceptors, the histidine kinase CheA and an adaptor protein, CheW. Although chemotaxis pathways represent the best understood signaling systems, a detailed mechanistic understanding of signal transduction has been hindered by the lack of a complete structural picture of the CSU and extended array. In this study, we present the structure of the complete CSU from phage ϕX174 E protein lysed Escherichia coli cells, determined using cryo-electron tomography and sub-tomogram averaging to 12-Å resolution. Our results provide new insight into previously poorly-resolved regions of the complex and offer a structural basis for designing new experiments to test mechanistic hypotheses.

mBio. September 2023