PT  - JOURNAL ARTICLE
AU  - Motwani, Tina
AU  - Lokareddy, Ravi K.
AU  - Dunbar, Carmen A.
AU  - Cortines, Juliana R.
AU  - Jarrold, Martin F.
AU  - Cingolani, Gino
AU  - Teschke, Carolyn M.
TI  - A viral scaffolding protein triggers portal ring oligomerization and incorporation during procapsid assembly
AID  - 10.1126/sciadv.1700423
DP  - 2017 Jul 01
TA  - Science Advances
PG  - e1700423
VI  - 3
IP  - 7
4099  - http://advances.sciencemag.org/content/3/7/e1700423.short
4100  - http://advances.sciencemag.org/content/3/7/e1700423.full
SO  - Sci Adv2017 Jul 01; 3
AB  - Most double-stranded DNA viruses package genetic material into empty precursor capsids (or procapsids) through a dodecameric portal protein complex that occupies 1 of the 12 vertices of the icosahedral lattice. Inhibiting incorporation of the portal complex prevents the formation of infectious virions, making this step an excellent target for antiviral drugs. The mechanism by which a sole portal assembly is selectively incorporated at the special vertex is unclear. We recently showed that, as part of the DNA packaging process for bacteriophage P22, the dodecameric procapsid portal changes conformation to a mature virion state. We report that preformed dodecameric rings of P22 portal protein, as opposed to portal monomers, incorporate into nascent procapsids, with preference for the procapsid portal conformation. Finally, a novel role for P22 scaffolding protein in triggering portal ring formation from portal monomers is elucidated and validated by incorporating de novo assembled portal rings into procapsids.