7z4w
gp6/gp15/gp16 connector complex of bacteriophage SPP1
Structural highlights
FunctionPORTL_BPSPP Forms the portal vertex of the capsid (PubMed:17363899). This portal plays critical roles in head assembly, genome packaging, neck/tail attachment, and genome ejection. The portal protein multimerizes as a single ring-shaped homododecamer arranged around a central channel. Binds to the terminase subunits to form the packaging machine.[1] Publication Abstract from PubMedNumerous viruses package their dsDNA genome into preformed capsids through a portal gatekeeper that is subsequently closed. We report the structure of the DNA gatekeeper complex of bacteriophage SPP1 (gp6(12)gp15(12)gp16(6)) in the post-DNA packaging state at 2.7 A resolution obtained by single particle cryo-electron microscopy. Comparison of the native SPP1 complex with assembly-naive structures of individual components uncovered the complex program of conformational changes leading to its assembly. After DNA packaging, gp15 binds via its C-terminus to the gp6 oligomer positioning gp15 subunits for oligomerization. Gp15 refolds its inner loops creating an intersubunit beta-barrel that establishes different types of contacts with six gp16 subunits. Gp16 binding and oligomerization is accompanied by folding of helices that close the portal channel to keep the viral genome inside the capsid. This mechanism of assembly has broad functional and evolutionary implications for viruses of the prokaryotic tailed viruses-herpesviruses lineage. CryoEM structure and assembly mechanism of a bacterial virus genome gatekeeper.,Orlov I, Roche S, Brasiles S, Lukoyanova N, Vaney MC, Tavares P, Orlova EV Nat Commun. 2022 Nov 26;13(1):7283. doi: 10.1038/s41467-022-34999-8. PMID:36435855[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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