Abstract

Bacterial 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 solved structures of the intact Salmonella flagellar basal body, 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. 

Biography

Emily Furlong is a postdoctoral researcher at the Victor Chang Cardiac Research Institute. She completed a BSc and Honours at the University of Queensland before undertaking a PhD at the Institute for Molecular Bioscience. Her PhD research focused on the structural and functional characterisation of an understudied class of copper resistance proteins from the uropathogen Proteus mirabilis. During her PhD, she spent 6 months at the University of Oxford learning cryo-electron microscopy (cryo-EM). Emily loved Oxford so much that she returned as a postdoctoral researcher in 2019 and spent two years continuing her cryo-EM training. During these two years, she worked on the structural characterisation of the bacterial flagellar motor. In 2021, Emily returned to Australia and has spent the past 12 months researching another molecular machine, ATP synthase.