Structural basis of multimodal adsorption and infection initiation by Vibrio phage Peru-2.

Phage Peru-2, isolated during the 1993 cholera outbreaks in Peru, is distinct from the three ICP phage lineages typically associated with epidemic Vibrio cholerae. The molecular basis of Peru-2 adsorption and infection initiation has remained unknown. Here, we combine single-particle cryo-electron microscopy (cryo-EM) and cryo-electron tomography (cryo-ET) to define the architecture and infection mechanisms of Peru-2 at high resolution. The mature virion comprises an icosahedral capsid decorated with minor capsid proteins and a short tail apparatus surrounded by six structurally flexible tailspikes. These tailspikes are enzymatically active in mediating phage attachment to the Vibrio polysaccharide (VPS), a key component of biofilms. Three internal core proteins form a disordered core adjacent to the portal, positioning them for release before genome ejection during infection initiation. Structural analyses further resolve pre-ejection, genome-ejection, and post-ejection intermediates of the tail apparatus, while cryo-ET imaging of infected cells reveals a multimodal adsorption strategy during infection initiation.