5w0k
From Proteopedia
Crystal structure of EBV gHgL/CL40/gp42 N-domain
Structural highlights
Function[GH_EBVB9] The heterodimer glycoprotein H-glycoprotein L is required for the fusion of viral and plasma membranes leading to virus entry into the host cell. Membrane fusion is mediated by the fusion machinery composed at least of gB and the heterodimer gH/gL. Fusion of EBV with B-lymphocytes requires the additional receptor-binding protein gp42, which forms a complex with gH/gL. May also be required for virus attachment to epithelial cells.[1] [GL_EBVB9] The heterodimer glycoprotein H-glycoprotein L is required for the fusion of viral and plasma membranes leading to virus entry into the host cell. Membrane fusion is mediated by the fusion machinery composed at least of gB and the heterodimer gH/gL. Fusion of EBV with B-lymphocytes requires the additional receptor-binding protein gp42, which forms a complex with gH/gL. May also be required for virus attachment to epithelial cells (By similarity). [GP42_EBVB9] Plays a role in virion attachment to host B-lymphocytes, through binding to leukocyte antigen (HLA) class II and subsequently participates in fusion of the virion with host membranes. May act as a tropism switch that directs fusion with B-lymphocytes and inhibits fusion with epithelial cells.[2] Publication Abstract from PubMedHerpesvirus entry into cells requires the coordinated action of multiple virus envelope glycoproteins, including gH, gL, and gB. For EBV, the gp42 protein assembles into complexes with gHgL heterodimers and binds HLA class II to activate gB-mediated membrane fusion with B cells. EBV tropism is dictated by gp42 levels in the virion, as it inhibits entry into epithelial cells while promoting entry into B cells. The gHgL and gB proteins are targets of neutralizing antibodies and potential candidates for subunit vaccine development, but our understanding of their neutralizing epitopes and the mechanisms of inhibition remain relatively unexplored. Here we studied the structures and mechanisms of two anti-gHgL antibodies, CL40 and CL59, that block membrane fusion with both B cells and epithelial cells. We determined the structures of the CL40 and CL59 complexes with gHgL using X-ray crystallography and EM to identify their epitope locations. CL59 binds to the C-terminal domain IV of gH, while CL40 binds to a site occupied by the gp42 receptor binding domain. CL40 binding to gHgL/gp42 complexes is not blocked by gp42 and does not interfere with gp42 binding to HLA class II, indicating that its ability to block membrane fusion with B cells represents a defect in gB activation. These data indicate that anti-gHgL neutralizing antibodies can block gHgL-mediated activation of gB through different surface epitopes and mechanisms. Inhibition of EBV-mediated membrane fusion by anti-gHgL antibodies.,Sathiyamoorthy K, Jiang J, Mohl BS, Chen J, Zhou ZH, Longnecker R, Jardetzky TS Proc Natl Acad Sci U S A. 2017 Sep 22. pii: 201704661. doi:, 10.1073/pnas.1704661114. PMID:28939750[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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