Document Type
Article
Publication Date
1-30-2017
Abstract
Tailed bacteriophages and herpesviruses assemble infectious particles via an empty precursor capsid (or 'procapsid') built by multiple copies of coat and scaffolding protein and by one dodecameric portal protein. Genome packaging triggers rearrangement of the coat protein and release of scaffolding protein, resulting in dramatic procapsid lattice expansion. Here, we provide structural evidence that the portal protein of the bacteriophage P22 exists in two distinct dodecameric conformations: an asymmetric assembly in the procapsid (PC-portal) that is competent for high affinity binding to the large terminase packaging protein, and a symmetric ring in the mature virion (MV-portal) that has negligible affinity for the packaging motor. Modelling studies indicate the structure of PC-portal is incompatible with DNA coaxially spooled around the portal vertex, suggesting that newly packaged DNA triggers the switch from PC- to MV-conformation. Thus, we propose the signal for termination of 'Headful Packaging' is a DNA-dependent symmetrization of portal protein.
Recommended Citation
Lokareddy, Ravi K.; Sankhala, Rajeshwer S.; Roy, Ankoor; Afonine, Pavel V.; Motwani, Tina; Teschke, Carolyn M M.; Parent, Kristin N.; and Cingolani, Gino, "Portal protein functions akin to a DNA-sensor that couples genome-packaging to icosahedral capsid maturation." (2017). Department of Biochemistry and Molecular Biology Faculty Papers. Paper 112.
https://jdc.jefferson.edu/bmpfp/112
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.
PubMed ID
28134243
Comments
This article has been peer reviewed. It is the author’s final published version in Nature Communications
Volume 8, January 2017, Article number 14310.
The published version is available at DOI: 10.1038/ncomms14310. Copyright © Lokareddy et al.