英国伯贝克学院Gabriel Waksman、Kévin Macé和美国华盛顿大学Qian Cong研究组合作解析了IV型分泌系统的冷冻电镜结构。相关论文于2022年6月22日发表于国际学术期刊《自然》杂志。
研究人员解析了一个2.8兆道尔顿T4SS复合物的高分辨率冷冻电镜(cryo-EM)结构，该复合物由92种多肽组成，是10种必需T4SS中8种参与菌毛生物发生的复合物。研究人员使用蛋白质界面共同进化分析将剩余的两个组件添加到结构模型中，以实现包括菌毛在内整个系统的重建。该结构揭示了T4SS中许多组件所需的异常大蛋白质-蛋白质相互作用网络，并提供了其调控菌毛发育独特机制的见解。
研究人员表示，细菌结合是将DNA（通常是质粒DNA）从供体细胞单向转移到受体细胞的基本过程。它是抗生素抗性基因在细菌种群内传播的主要方式。在革兰氏阴性细菌中，结合由供体细胞产生并嵌入其外膜和内膜的大型运输装置-结合型IV分泌系统 (T4SS) 所介导。T4SS还调控了一种长的细胞外细丝-结合菌毛的产生，这是DNA转移所必需的。
附：英文原文
Title: Cryo-EM structure of a type IV secretion system
Author: Mac, Kvin, Vadakkepat, Abhinav K., Redzej, Adam, Lukoyanova, Natalya, Oomen, Clasien, Braun, Nathalie, Ukleja, Marta, Lu, Fang, Costa, Tiago R. D., Orlova, Elena V., Baker, David, Cong, Qian, Waksman, Gabriel
Issue&Volume: 2022-06-22
Abstract: Bacterial conjugation is the fundamental process of unidirectional transfer of DNAs, often plasmid DNAs, from a donor cell to a recipient cell1. It is the primary means by which antibiotic resistance genes spread among bacterial populations2,3. In Gram-negative bacteria, conjugation is mediated by a large transport apparatus—the conjugative type IV secretion system (T4SS)—produced by the donor cell and embedded in both its outer and inner membranes. The T4SS also elaborates a long extracellular filament—the conjugative pilus—that is essential for DNA transfer4,5. Here we present a high-resolution cryo-electron microscopy (cryo-EM) structure of a 2.8 megadalton T4SS complex composed of 92 polypeptides representing 8 of the 10 essential T4SS components involved in pilus biogenesis. We added the two remaining components to the structural model using co-evolution analysis of protein interfaces, to enable the reconstitution of the entire system including the pilus. This structure describes the exceptionally large protein–protein interaction network required to assemble the many components that constitute a T4SS and provides insights on the unique mechanism by which they elaborate pili.
DOI: 10.1038/s41586-022-04859-y
Source: https://www.nature.com/articles/s41586-022-04859-y
Nature：《自然》，创刊于1869年。隶属于施普林格·自然出版集团，最新IF：69.504
官方网址：http://www.nature.com/
投稿链接：http://www.nature.com/authors/submit_manuscript.html
本期文章：《自然》：Online/在线发表
