7bqx
From Proteopedia
Epstein-Barr virus, C5 portal vertex
Structural highlights
FunctionTRX1_EBVB9 Structural component of the T=16 icosahedral capsid. The capsid is composed of pentamers and hexamers of major capsid protein/MCP, which are linked together by heterotrimers called triplexes. These triplexes are formed by a single molecule of triplex protein 1/TRX1 and two copies of triplex protein 2/TRX2. Additionally, TRX1 is required for efficient transport of TRX2 to the nucleus, which is the site of capsid assembly. Publication Abstract from PubMedEpstein-Barr virus (EBV) is the primary cause of infectious mononucleosis and has been shown to be closely associated with various malignancies. Here, we present a complete atomic model of EBV, including the icosahedral capsid, the dodecameric portal and the capsid-associated tegument complex (CATC). Our in situ portal from the tegumented capsid adopts a closed conformation with its channel valve holding the terminal viral DNA and with its crown region firmly engaged by three layers of ring-like dsDNA, which, together with the penton flexibility, effectively alleviates the capsid inner pressure placed on the portal cap. In contrast, the CATCs, through binding to the flexible penton vertices in a stoichiometric manner, accurately increase the inner capsid pressure to facilitate the pressure-driven genome delivery. Together, our results provide important insights into the mechanism by which the EBV capsid, portal, packaged genome and the CATCs coordinately achieve a pressure balance to simultaneously benefit both viral genome retention and ejection. CryoEM structure of the tegumented capsid of Epstein-Barr virus.,Li Z, Zhang X, Dong L, Pang J, Xu M, Zhong Q, Zeng MS, Yu X Cell Res. 2020 Jul 3. pii: 10.1038/s41422-020-0363-0. doi:, 10.1038/s41422-020-0363-0. PMID:32620850[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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