Structural changes of tailless bacteriophage ?X174 during penetration of bacterial cell walls.

ABSTRACT: Unlike tailed bacteriophages, which use a preformed tail for transporting their genomes into a host bacterium, the ssDNA bacteriophage ?X174 is tailless. Using cryo-electron microscopy and time-resolved small-angle X-ray scattering, we show that lipopolysaccharides (LPS) form bilayers that interact with ?X174 at an icosahedral fivefold vertex and induce single-stranded (ss) DNA genome ejection. The structures of ?X174 complexed with LPS have been determined for the pre- and post-ssDNA ejection states. The ejection is initiated by the loss of the G protein spike that encounters the LPS, followed by conformational changes of two polypeptide loops on the major capsid F proteins. One of these loops mediates viral attachment, and the other participates in making the fivefold channel at the vertex contacting the LPS.

SUBMITTER: Sun Y 

PROVIDER: S-EPMC5748221 | biostudies-literature | 2017 Dec

REPOSITORIES: biostudies-literature