Molecular structure of the intact bacterial flagellar basal body

• DOI: 10.1038/s41564-021-00895-y
• Publication Date: 2021-05-03T10:49:55Z
• Authors: Steven Johnson; Emily J. Furlong; Justin C. Deme; Ashley L. Nord; Joseph J. E. Caesar; Fabienne F. V. Ch...; Richard M. Berry; Kelly T. Hughes; Susan M. Lea
• Keywords: 0301 basic medicine; 03 medical and health sciences; [SDV.BBM.BS]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Structural Biology [q-bio.BM]; Bacterial Proteins; Flagella; Salmonella; Cryoelectron Microscopy; Article; Basal Bodies

AbstractBacterial flagella self-assemble a strong, multi-component drive shaft that couples rotation in the inner membrane to the microns-long flagellar filament that powers bacterial swimming in viscous fluids. We here present structures of the intact Salmonella flagellar basal body, solved using cryo-electron microscopy to resolutions between 2.2 and 3.7 Å. The structures reveal molecular details of how 173 protein molecules of 13 different types assemble into a complex spanning two membranes and a cell wall. The helical drive shaft at one end is intricately interwoven with the inner membrane rotor component, and at the other end passes through a molecular bearing that is anchored in the outer membrane via interactions with the lipopolysaccharide. The in situ structure of a protein complex capping the drive shaft provides molecular insight into the assembly process of this molecular machine.