5JJ3

Refined Structure of the Mature Virion Conformation of P22 Portal Protein

Summary for 5JJ3

• Entry DOI: 10.2210/pdb5jj3/pdb
• Related: 3LJ5 5JJ1
• Descriptor: Portal protein (1 entity in total)
• Functional Keywords: portal protein, dodecamer, packaging motor, procapsid, viral protein
• Biological source: Enterobacteria phage P22
• Total number of polymer chains: 12
• Total formula weight: 993952.50

Authors

Lokareddy, R.K.,Sankhala, R.S.,Cingolani, G. (deposition date: 2016-04-22, release date: 2017-02-08, Last modification date: 2023-09-27)

Primary citation

Lokareddy, R.K.,Sankhala, R.S.,Roy, A.,Afonine, P.V.,Motwani, T.,Teschke, C.M.,Parent, K.N.,Cingolani, G.
Portal protein functions akin to a DNA-sensor that couples genome-packaging to icosahedral capsid maturation.
Nat Commun, 8:14310-14310, 2017

PubMed 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.

PubMed: 28134243
DOI: 10.1038/ncomms14310

Experimental method

X-RAY DIFFRACTION (7 Å)