Phi29 assembly intermediates reveal how scaffold interactions with capsid protein drive capsid construction and maturation.

ABSTRACT: The self-assembly of bacteriophage capsids from major capsid proteins (MCPs) and scaffolding proteins (SPs) and the subsequent expansion of these capsids are essential steps in bacteriophage life cycles. However, the mechanism by which assembly occurs remains poorly understood, and few intermediate states are available to illuminate the expansion of meta-stable procapsids into robust mature capsids. Here, we present the structure of a partially expanded phi29 procapsid that reveals distinct conformations of MCPs and allows visualization of SPs in multiple oligomeric states. These results suggest that formation of SP dimers, tetramers, and higher-order oligomers drives dissociation of SP from MCP to actuate capsid expansion. Hexons expand first, and we propose penton maturation is delayed b

SUBMITTER: Woodson M 

PROVIDER: S-EPMC11922011 | biostudies-literature | 2025 Mar

REPOSITORIES: biostudies-literature