Protein P7 of the Cystovirus φ6 Is Located at the Three-Fold Axis of the Unexpanded Procapsid

Authors

Garrett Katz, CUNY City College
Hui Wei, CUNY City College
Alexandra Alimova, CUNY City College
Al Katz, CUNY City College
David Gene Morgan, Indiana University
Paul Gottlieb, CUNY City College

Document Type

Article

Publication Date

October 2012

Abstract

The objective of this study was to determine the location of protein P7, the RNA packaging factor, in the procapsid of the φ6 cystovirus. A comparison of cryo-electron microscopy high-resolution single particle reconstructions of the φ6 complete unexpanded procapsid, the protein P2-minus procapsid (P2 is the RNA directed RNA-polymerase), and the P7-minus procapsid, show that prior to RNA packaging the P7 protein is located near the three-fold axis of symmetry. Difference maps highlight the precise position of P7 and demonstrate that in P7-minus particles the P2 proteins are less localized with reduced densities at the three-fold axes. We propose that P7 performs the mechanical function of stabilizing P2 on the inner protein P1 shell which ensures that entering viral single-stranded RNA is replicated.

Comments

This work was originally published in PLoS ONE, available at doi:10.1371/journal.pone.0047489.