Three-dimensional structure of the bacteriophage P22 tail machine.

The tail of the bacteriophage P22 is composed of multiple protein components and integrates various biological functions that are crucial to the assembly and infection of the phage. The three-dimensional structure of the P22 tail machine determined by electron cryo-microscopy and image reconstruction reveals how the five types of polypeptides present as 51 subunits are organized into this molecular machine through twelve-, six- and three-fold symmetry, and provides insights into molecular events during host cell attachment and phage DNA translocation.