PDF(Pubmed)
Abstract：
The flagellotropic bacteriophage χ (Chi) infects bacteria via the flagellar filament. Despite years of study, its structural architecture remains partly characterized. Through cryo-EM, we unveil χ\'s nearly complete structure, encompassing capsid, neck, tail, and tail tip. While the capsid and tail resemble phage YSD1, the neck and tail tip reveal new proteins and their arrangement. The neck shows a unique conformation of the tail tube protein, forming a socket-like structure for attachment to the neck. The tail tip comprises four proteins, including distal tail protein (DTP), two baseplate hub proteins (BH1P and BH2P), and tail tip assembly protein (TAP) exhibiting minimal organization compared to other siphophages. Deviating from the consensus in other siphophages, DTP in χ forms a trimeric assembly, reducing tail symmetry from 6-fold to 3-fold at the tip. These findings illuminate the previously unexplored structural organization of χ\'s neck and tail tip.
摘要：
鞭毛型噬菌体χ(Chi)通过鞭毛丝感染细菌。尽管经过多年的研究,它的结构架构仍然具有部分特征。通过低温EM，我们揭示了χ的几乎完整的结构，包括衣壳，脖子,尾巴,和尾尖。虽然衣壳和尾部类似于噬菌体YSD1，但颈部和尾部尖端揭示了新的蛋白质及其排列。颈部显示出独特的尾管蛋白构象，形成连接到颈部的插座状结构。尾尖包含四种蛋白质，包括远端尾蛋白（DTP），两个基板hub蛋白（BHylP和BH2P），和尾尖组装蛋白（TAP），与其他虹吸管相比，显示出最小的组织。偏离了其他虹吸管的共识，χ中的DTP形成三聚体组装，在尖端将尾巴对称性从6倍减少到3倍。这些发现阐明了以前未探索的χ的颈部和尾部尖端的结构组织。
