Cohen Eli J, Drobnič Tina, Ribardo Deborah A, Yoshioka Aoba, Umrekar Trishant, Guo Xuefei, Fernandez Jose-Jesus, Brock Emma E, Wilson Laurence, Nakane Daisuke, Hendrixson David R, Beeby Morgan
Department of Life Sciences, Imperial College London, London SW7 2AZ, UK.
Department of Life Sciences, Imperial College London, London SW7 2AZ, UK.
Dev Cell. 2024 Dec 16;59(24):3306-3321.e5. doi: 10.1016/j.devcel.2024.09.008. Epub 2024 Oct 2.
The flagellar motors of Campylobacter jejuni (C. jejuni) and related Campylobacterota (previously epsilonproteobacteria) feature 100-nm-wide periplasmic "basal disks" that have been implicated in scaffolding a wider ring of additional motor proteins to increase torque, but the size of these disks is excessive for a role solely in scaffolding motor proteins. Here, we show that the basal disk is a flange that braces the flagellar motor during disentanglement of its flagellar filament from interactions with the cell body and other filaments. We show that motor output is unaffected when we shrink or displace the basal disk, and suppressor mutations of debilitated motors occur in flagellar-filament or cell-surface glycosylation pathways, thus sidestepping the need for a flange to overcome the interactions between two flagellar filaments and between flagellar filaments and the cell body. Our results identify unanticipated co-dependencies in the evolution of flagellar motor structure and cell-surface properties in the Campylobacterota.
空肠弯曲菌（C. jejuni）及相关弯曲菌门细菌（以前称为ε-变形菌门）的鞭毛马达具有宽度为100纳米的周质“基盘”，这些基盘被认为可作为更广泛的额外马达蛋白环的支架，以增加扭矩，但仅从作为马达蛋白的支架作用来看，这些基盘的尺寸过大。在这里，我们表明，基盘是一个凸缘，在鞭毛丝与细胞体及其他丝状物的相互作用解缠过程中支撑鞭毛马达。我们发现，当缩小或移动基盘时，马达输出不受影响，并且在鞭毛丝或细胞表面糖基化途径中会出现功能减弱的马达的抑制突变，从而无需凸缘来克服两根鞭毛丝之间以及鞭毛丝与细胞体之间的相互作用。我们的研究结果揭示了弯曲菌门细菌鞭毛马达结构和细胞表面特性进化中意想不到的共同依赖性。
