Lytic podophages (VP1–VP5) play crucial roles in subtyping Vibrio cholerae O1 biotype El Tor. However, until now no structures of these phages have been available, which hindered our understanding of the molecular mechanisms of infection and DNA release. Here, we determined the cryoelectron microscopy (cryo-EM) structures of mature and DNA-ejected VP1 structures at near-atomic and subnanometer resolutions, respectively. The VP1 head is composed of 415 copies of the major capsid protein gp7 and 11 turret-shaped spikes. The VP1 tail consists of an adapter, a nozzle, a slender ring, and a tail needle, and is flanked by three extended fibers I and six trimeric fibers II. Conformational changes of fiber II in DNA-ejected VP1 may cause the release of the tail needle and core proteins, forming an elongated tail channel. Our structures provide insights into the molecular mechanisms of infection and DNA release for podophages with a tail needle.

中文翻译：

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霍乱弧菌分型足噬菌体 VP1 在两种状态下的三维结构


裂解足噬菌体 （VP1-VP5） 在霍乱弧菌 O1 生物型 El Tor 的亚型中起着至关重要的作用。然而，到目前为止，还没有这些噬菌体的结构可用，这阻碍了我们对感染和 DNA 释放的分子机制的理解。在这里，我们分别以近原子和亚纳米分辨率确定了成熟和 DNA 喷射的 VP1 结构的冷冻电子显微镜 （cryo-EM） 结构。VP1 头部由 415 个主要衣壳蛋白 gp7 拷贝和 11 个炮塔状刺突组成。VP1 尾部由一个适配器、一个喷嘴、一个细长环和一个尾针组成，两侧是三根延长纤维 I 和六根三聚体纤维 II。DNA 射出的 VP1 中纤维 II 的构象变化可能导致尾针和核心蛋白的释放，形成细长的尾通道。我们的结构提供了对尾针足噬菌体感染和 DNA 释放的分子机制的见解。