Structural highlights
3ja7 is a 12 chain structure. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
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| Resources: | FirstGlance, OCA, RCSB, PDBsum |
Function
[PORTL_BPT4] Forms the portal vertex of the capsid (PubMed:2685327, PubMed:24126213). 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. Attaches to the host inner membrane most likely through interaction with host yidC and forms together with chaperone gp40 an initiator complex to form the prohead.[1] [2]
Publication Abstract from PubMed
The structure and assembly of bacteriophage T4 has been extensively studied. However, the detailed structure of the portal protein remained unknown. Here we report the structure of the bacteriophage T4 portal assembly, gene product 20 (gp20), determined by cryo-electron microscopy (cryo-EM) to 3.6 A resolution. In addition, analysis of a 10 A resolution cryo-EM map of an empty prolate T4 head shows how the dodecameric portal assembly interacts with the capsid protein gp23 at the special pentameric vertex. The gp20 structure also verifies that the portal assembly is required for initiating head assembly, for attachment of the packaging motor, and for participation in DNA packaging. Comparison of the Myoviridae T4 portal structure with the known portal structures of phi29, SPP1 and P22, representing Podo- and Siphoviridae, shows that the portal structure probably dates back to a time when self-replicating microorganisms were being established on Earth.
Cryo-EM structure of the bacteriophage T4 portal protein assembly at near-atomic resolution.,Sun L, Zhang X, Gao S, Rao PA, Padilla-Sanchez V, Chen Z, Sun S, Xiang Y, Subramaniam S, Rao VB, Rossmann MG Nat Commun. 2015 Jul 6;6:7548. doi: 10.1038/ncomms8548. PMID:26144253[3]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Padilla-Sanchez V, Gao S, Kim HR, Kihara D, Sun L, Rossmann MG, Rao VB. Structure-function analysis of the DNA translocating portal of the bacteriophage T4 packaging machine. J Mol Biol. 2014 Mar 6;426(5):1019-38. doi: 10.1016/j.jmb.2013.10.011. Epub 2013 , Oct 11. PMID:24126213 doi:http://dx.doi.org/10.1016/j.jmb.2013.10.011
- ↑ Michaud G, Zachary A, Rao VB, Black LW. Membrane-associated assembly of a phage T4 DNA entrance vertex structure studied with expression vectors. J Mol Biol. 1989 Oct 20;209(4):667-81. PMID:2685327 doi:http://dx.doi.org/10.1016/0022-2836(89)90599-8
- ↑ Sun L, Zhang X, Gao S, Rao PA, Padilla-Sanchez V, Chen Z, Sun S, Xiang Y, Subramaniam S, Rao VB, Rossmann MG. Cryo-EM structure of the bacteriophage T4 portal protein assembly at near-atomic resolution. Nat Commun. 2015 Jul 6;6:7548. doi: 10.1038/ncomms8548. PMID:26144253 doi:http://dx.doi.org/10.1038/ncomms8548
