噬菌体phi92非对称结构揭示了一种新颖的多套尾纤维的纳米机器 - 2025年 第44卷 第1期 - 电子显微学报

噬菌体phi92非对称结构揭示了一种新颖的多套尾纤维的纳米机器

刘媛媛#,周俊权#,张烨伟,郑 静*,刘红荣*

噬菌体phi92非对称结构揭示了一种新颖的多套尾纤维的纳米机器
刘媛媛#,周俊权#,张烨伟,郑   静*,刘红荣*
(湖南师范大学交叉科学研究院,物理与电子科学学院,物质微结构与功能湖南省重点实验室,低维量子结构与调控教育部重点实验室,湖南 长沙  410082)

摘   要   肌尾噬菌体phi92具有广泛的宿主范围,能感染有polySia(聚唾液酸)荚膜和没有polySia荚膜的细菌。然而完整高分辨率结构的缺失阻碍了对phi92感染和尾部收缩机制的理解。本研究利用冷冻电镜单颗粒技术获得了phi92成熟颗粒近原子分辨率对称失配结构,搭建了包括头部、颈部、尾躯干域以及基板各蛋白分子的全原子结构模型。本研究首次发现了基板上有三套尾纤维(I,II和III)的肌尾噬菌体,phi92基板上的异源三聚体楔形蛋白比已报道的简单基板的可收缩的纳米机器的楔形蛋白更为复杂和独特,为连接多套尾纤维提供了更多的吸附位点。本研究为其它具有多套尾纤维的可收缩的纳米机器的感染和尾部收缩机制提供了更多的结构基础。
关键词   噬菌体phi92;冷冻电镜;对称失配结构;尾纤维;polySia荚膜
中图分类号:Q71;Q-336;Q518.2;Q615  文献标识码:ADoi:10.3969/j.issn.1000-6281.2025.01.008

 

Asymmetric structure of phage phi92 reveals a novel nanomachine with multi-types of tail fibers
LIU Yuanyuan 1#,ZHOU Junquan 1#,ZHANG Yewei 1,ZHENG Jing 1*,LIU Hongrong 1*
(Institute of Interdisciplinary Studies, School of Physics and Electronics, Key Laboratory for Matter Microstructure and Function of Hunan Province, Key Laboratory of Low-dimensional Quantum Structures and Quantum Control, Hunan Normal University, Changsha 410082, China)

Abstract   Myophage phi92 exhibits a broad host range, enabling infection of bacteria with or without polySia (polysialic acid) capsules. Nevertheless, the lack of a high-resolution structure for phi92 has limited further understanding into its molecular mechanisms of infection and tail contraction. This study employed cryo-electron microscopy (cryo-EM) to resolve the asymmetric structure of the mature phi92 to near-atomic resolution and built atomic models for the majority of its proteins, including the head, neck, tail trunk, and simple baseplate. It is noteworthy that phage phi92 is the first reported myophage to possess three distinct types (I, II, and III) of tail fibers. Its heterotrimeric wedges in the baseplate are more intricate and innovative than those observed in previously reported contractile nanomachines with a simple baseplate, offering a greater number of attachment sites for multi-type tail fibers. This study provides structural insights for the molecular mechanisms of infection and tail contraction for contractile nanomachines with multiple types of tail fibers.
Keywords   bacteriophage phi92;Cryo-EM;symmetry-mismatch structure; tail fiber;polySia capsule