Structural basis of bacteriophage T5 infection trigger and E. coli cell wall perforation

Most bacteriophages present a tail allowing host recognition, cell wall perforation, and viral DNA channeling from the capsid to the infected bacterium cytoplasm. The majority of tailed phages bear a long flexible tail (Si-phoviridae) at the tip of which receptor binding proteins (RBPs) specifically interact with their host, triggering infection. In siphophage T5, the unique RBP is located at the extremity of a central fiber. We present the struc-tures of T5 tail tip, determined by cryo-electron microscopy before and after interaction with its E. coli receptor, FhuA, reconstituted into nanodisc. These structures bring out the important conformational changes under-gone by T5 tail tip upon infection, which include bending of T5 central fiber on the side of the tail tip, tail an-choring to the membrane, tail tube opening, and formation of a transmembrane channel. The data allow to detail the first steps of an otherwise undescribed infection mechanism.

Automated summary

The structures of the T5 tail tip before and after interaction with its receptor, FhuA, have been determined using cryo-electron microscopy. These structures reveal important conformational changes, such as bending of the central fiber, anchoring of the tail to the membrane, opening of the tail tube, and formation of a transmembrane channel. This provides detailed insights into the initial steps of the infection mechanism.