Structure of a headful DNA-packaging bacterial virus at 2.9 A resolution by electron cryo-microscopy.

ABSTRACT: The enormous prevalence of tailed DNA bacteriophages on this planet is enabled by highly efficient self-assembly of hundreds of protein subunits into highly stable capsids. These capsids can stand with an internal pressure as high as ?50 atmospheres as a result of the phage DNA-packaging process. Here we report the complete atomic model of the headful DNA-packaging bacteriophage Sf6 at 2.9 Å resolution determined by electron cryo-microscopy. The structure reveals the DNA-inflated, tensed state of a robust protein shell assembled via noncovalent interactions. Remarkable global conformational polymorphism of capsid proteins, a network formed by extended N arms, mortise-and-tenon-like intercapsomer joints, and abundant ?-sheet-like mainchain:mainchain intermolecular interactions, confers significant strength yet also flexibility required for capsid assembly and DNA packaging. Differential formations of the hexon and penton are mediated by a drastic ?-helix-to-?-strand structural transition. The assembly scheme revealed here may be common among tailed DNA phages and herpesviruses.

SUBMITTER: Zhao H 

PROVIDER: S-EPMC5389284 | biostudies-literature | 2017 Apr

REPOSITORIES: biostudies-literature