Zheng Jing, Chen Wenyuan, Xiao Hao, Yang Fan, Song Jingdong, Cheng Lingpeng, Liu Hongrong
Institute of Interdisciplinary Studies, Key Laboratory for Matter Microstructure and Function of Hunan Province, Key Laboratory of Low-dimensional Quantum Structures and Quantum Control, School of Physics and Electronics, Hunan Normal University, Changsha 410082, China.
Institute of Interdisciplinary Studies, Key Laboratory for Matter Microstructure and Function of Hunan Province, Key Laboratory of Low-dimensional Quantum Structures and Quantum Control, School of Physics and Electronics, Hunan Normal University, Changsha 410082, China; State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 100052, China.
J Mol Biol. 2023 Oct 15;435(20):168258. doi: 10.1016/j.jmb.2023.168258. Epub 2023 Sep 1.
Bacteriophage tail fibers (or called tail spikes) play a critical role in the early stage of infection by binding to the bacterial surface. Podophages with known structures usually possess one or two types of fibers. Here, we resolved an asymmetric structure of the podophage GP4 to near-atomic resolution by cryo-EM. Our structure revealed a symmetry-mismatch relationship between the components of the GP4 tail with previously unseen topologies. In detail, two dodecameric adaptors (adaptors I and II), a hexameric nozzle, and a tail needle form a conserved tail body connected to a dodecameric portal occupying a unique vertex of the icosahedral head. However, five chain-like extended fibers (fiber I) and five tulip-like short fibers (fiber II) are anchored to a 15-fold symmetric fiber-tail adaptor, encircling the adaptor I, and six bamboo-like trimeric fibers (fiber III) are connected to the nozzle. Five fibers I, each composed of five dimers of the protein gp80 linked by an elongated rope protein, are attached to the five edges of the tail vertex of the icosahedral head. In this study, we identified a new structure of the podophage with three types of tail fibers, and such phages with different types of fibers may have a broad host range and/or infect host cells with considerably high efficiency, providing evolutionary advantages in harsh environments.
噬菌体尾丝（或称为尾刺）通过与细菌表面结合在感染早期发挥关键作用。具有已知结构的短尾噬菌体通常拥有一种或两种类型的尾丝。在这里，我们通过冷冻电镜解析了短尾噬菌体GP4的不对称结构，分辨率接近原子水平。我们的结构揭示了GP4尾部各组件之间存在一种具有前所未见拓扑结构的对称不匹配关系。具体而言，两个十二聚体衔接蛋白（衔接蛋白I和II）、一个六聚体喷嘴和一个尾针形成一个保守的尾体，该尾体连接到占据二十面体头部独特顶点的十二聚体门户。然而，五条链状延伸纤维（纤维I）和五条郁金香状短纤维（纤维II）锚定在一个15重对称的纤维 - 尾衔接蛋白上，环绕着衔接蛋白I，并且六条竹状三聚体纤维（纤维III）连接到喷嘴。五条纤维I，每条由通过一条细长的绳状蛋白连接的五个gp80蛋白二聚体组成，附着在二十面体头部尾顶点的五条边上。在本研究中，我们鉴定出一种具有三种类型尾丝的短尾噬菌体新结构，并且这种具有不同类型尾丝的噬菌体可能具有广泛的宿主范围和/或以相当高的效率感染宿主细胞，在恶劣环境中提供进化优势。
