Bacteriophage genome gatekeeper

摘要

"Tailed" bacteriophages initiate the bacterium-killing process by firing viral DNA through a gunbarrel-like tail tube. Before contact with the bacterium, the DNA is packed under extremely high pressure in the phage capsid and is restrained by a plug connecting the capsid to the tail. This plug, or connector, is the gatekeeper controlling DNA release. Previously, researchers had obtained a cryo-EM electron density map of the whole portal system, but higher resolution information was lacking. Sophie Lhuillier et al. report the pseudo-atomic structure of the connector of the model tailed phage SPP1, with details that reveal the mechanism that keeps the portal closed. The SPP1 connector is built from dodecamers of the portal protein gp6, the "adaptor" protein gpl5, and the "stopper" gpl6.