Structure of a headful DNA-packaging bacterial virus at 2.9 angstrom resolution by electron cryo-microscopy.
Zhao, H., Li, K., Lynn, A.Y., Aron, K.E., Yu, G., Jiang, W., Tang, L.(2017) Proc Natl Acad Sci U S A 114: 3601-3606
- PubMed: 28320961 
- DOI: https://doi.org/10.1073/pnas.1615025114
- Primary Citation of Related Structures:  
5L35 - PubMed 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 β-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 α-helix-to-β-strand structural transition. The assembly scheme revealed here may be common among tailed DNA phages and herpesviruses.
Organizational Affiliation: 
Department of Molecular Biosciences, University of Kansas, Lawrence, KS 66045.