Structural highlights
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Function
[G9I257_HHV2] Participates in the assembly of the infectious particles by decorating the outer surface of the capsid shell and thus forming a layer between the capsid and the tegument. Complexes composed of the major capsid protein and small capsomere-interacting protein/SCP assemble together in the host cytoplasm and are translocated to the nucleus, where they accumulate and participate in capsid assembly.[HAMAP-Rule:MF_04020] [G9I240_HHV2] Self-assembles to form an icosahedral capsid with a T=16 symmetry, about 200 nm in diameter, and consisting of 150 hexons and 12 pentons (total of 162 capsomers). Hexons form the edges and faces of the capsid and are each composed of six MCP molecules. In contrast, one penton is found at each of the 12 vertices. Eleven of the pentons are MCP pentamers, while the last vertex is occupied by the portal complex. The capsid is surrounded by a layer of proteinaceous material designated the tegument which, in turn, is enclosed in an envelope of host cell-derived lipids containing virus-encoded glycoproteins.[HAMAP-Rule:MF_04016] [A0A1U9ZFW1_HHV2] 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.[HAMAP-Rule:MF_04018] [G9I239_HHV2] 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.[HAMAP-Rule:MF_04019]
Publication Abstract from PubMed
Structurally and genetically, human herpesviruses are among the largest and most complex of viruses. Using cryo-electron microscopy (cryo-EM) with an optimized image reconstruction strategy, we report the herpes simplex virus type 2 (HSV-2) capsid structure at 3.1 angstroms, which is built up of about 3000 proteins organized into three types of hexons (central, peripentonal, and edge), pentons, and triplexes. Both hexons and pentons contain the major capsid protein, VP5; hexons also contain a small capsid protein, VP26; and triplexes comprise VP23 and VP19C. Acting as core organizers, VP5 proteins form extensive intermolecular networks, involving multiple disulfide bonds (about 1500 in total) and noncovalent interactions, with VP26 proteins and triplexes that underpin capsid stability and assembly. Conformational adaptations of these proteins induced by their microenvironments lead to 46 different conformers that assemble into a massive quasisymmetric shell, exemplifying the structural and functional complexity of HSV.
Cryo-EM structure of a herpesvirus capsid at 3.1 A.,Yuan S, Wang J, Zhu D, Wang N, Gao Q, Chen W, Tang H, Wang J, Zhang X, Liu H, Rao Z, Wang X Science. 2018 Apr 6;360(6384). pii: 360/6384/eaao7283. doi:, 10.1126/science.aao7283. PMID:29622627[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Yuan S, Wang J, Zhu D, Wang N, Gao Q, Chen W, Tang H, Wang J, Zhang X, Liu H, Rao Z, Wang X. Cryo-EM structure of a herpesvirus capsid at 3.1 A. Science. 2018 Apr 6;360(6384). pii: 360/6384/eaao7283. doi:, 10.1126/science.aao7283. PMID:29622627 doi:http://dx.doi.org/10.1126/science.aao7283
