2kca

From Proteopedia

GP16

Structural highlights

2kca is a 1 chain structure with sequence from Bacillus phage SPP1. Full experimental information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	Solution NMR
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

HCP16_BPSPP Functions as a stopper that is part of the head-tail connector and that locks the viral DNA in the capsid. Following tail attachment to the entry receptor, seems to open by a diaphragm-like motion, allowing the genome to exit the capsid through the tail tube to the host cell. During assembly, functions as a docking platform which the preassembled tail tapered by the head-tail joining protein gp17 can bind to.^[1]

Evolutionary Conservation

Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.

Publication Abstract from PubMed

In many bacterial viruses and in certain animal viruses, the double-stranded DNA genome enters and exits the capsid through a portal gatekeeper. We report a pseudoatomic structure of a complete portal system. The bacteriophage SPP1 gatekeeper is composed of dodecamers of the portal protein gp6, the adaptor gp15, and the stopper gp16. The solution structures of gp15 and gp16 were determined by NMR. They were then docked together with the X-ray structure of gp6 into the electron density of the approximately 1-MDa SPP1 portal complex purified from DNA-filled capsids. The resulting structure reveals that gatekeeper assembly is accompanied by a large rearrangement of the gp15 structure and by folding of a flexible loop of gp16 to form an intersubunit parallel beta-sheet that closes the portal channel. This stopper system prevents release of packaged DNA. Disulfide cross-linking between beta-strands of the stopper blocks the key conformational changes that control genome ejection from the virus at the beginning of host infection.

Structure of bacteriophage SPP1 head-to-tail connection reveals mechanism for viral DNA gating.,Lhuillier S, Gallopin M, Gilquin B, Brasiles S, Lancelot N, Letellier G, Gilles M, Dethan G, Orlova EV, Couprie J, Tavares P, Zinn-Justin S Proc Natl Acad Sci U S A. 2009 May 26;106(21):8507-12. Epub 2009 May 11. PMID:19433794^[2]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Chaban Y, Lurz R, Brasiles S, Cornilleau C, Karreman M, Zinn-Justin S, Tavares P, Orlova EV. Structural rearrangements in the phage head-to-tail interface during assembly and infection. Proc Natl Acad Sci U S A. 2015 May 19. pii: 201504039. PMID:25991862 doi:http://dx.doi.org/10.1073/pnas.1504039112
↑ Lhuillier S, Gallopin M, Gilquin B, Brasiles S, Lancelot N, Letellier G, Gilles M, Dethan G, Orlova EV, Couprie J, Tavares P, Zinn-Justin S. Structure of bacteriophage SPP1 head-to-tail connection reveals mechanism for viral DNA gating. Proc Natl Acad Sci U S A. 2009 May 26;106(21):8507-12. Epub 2009 May 11. PMID:19433794