Atypical chemoreceptor arrays accommodate high membrane curvature.
Publication Type:Journal Article
Source:Nat Commun, Volume 11, Issue 1, p.5763 (2020)
Keywords:Amino Acid Sequence, Bacterial Proteins, Cell Membrane, Chemoreceptor Cells, Chemotaxis, Conserved Sequence, Escherichia coli, Gene Deletion, Histidine Kinase, Protein Domains, Sequence Homology, Amino Acid, Treponema
<p>The prokaryotic chemotaxis system is arguably the best-understood signaling pathway in biology. In all previously described species, chemoreceptors organize into a hexagonal (P6 symmetry) extended array. Here, we report an alternative symmetry (P2) of the chemotaxis apparatus that emerges from a strict linear organization of the histidine kinase CheA in Treponema denticola cells, which possesses arrays with the highest native curvature investigated thus far. Using cryo-ET, we reveal that Td chemoreceptor arrays assume an unusual arrangement of the supra-molecular protein assembly that has likely evolved to accommodate the high membrane curvature. The arrays have several atypical features, such as an extended dimerization domain of CheA and a variant CheW-CheR-like fusion protein that is critical for maintaining an ordered chemosensory apparatus. Furthermore, the previously characterized Td oxygen sensor ODP influences CheA ordering. These results suggest a greater diversity of the chemotaxis signaling system than previously thought.</p>