Receptor Binding-Induced Conformational Changes in Herpes Simplex Virus Glycoprotein D Permit Interaction with the gH/gL Complex to Activate Fusion.
Receptor Binding-Induced Conformational Changes in Herpes Simplex Virus Glycoprotein D Permit Interaction with the gH/gL Complex to Activate Fusion.
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DOI：
10.3390/v15040895
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发表时间：
2023-03-30
期刊：
影响因子：
--
通讯作者：
Cohen GH
中科院分区：
文献类型：
--
作者：
Atanasiu D;Saw WT;Cairns TM;Friedman HM;Eisenberg RJ;Cohen GH
单纯疱疹病毒（HSV）需要四种必需的病毒粒子糖蛋白-gD、gH、gL和gB-用于病毒进入和细胞融合。为了启动融合，受体结合蛋白gD与两种主要细胞受体HVEM或nectin-1之一相互作用。一旦gD与受体结合，通过gH/gL异二聚体和gB进行融合。游离和受体结合的gD晶体结构的比较显示，受体结合结构域位于gD的N-末端和核心的残基内。有问题的是，C-末端横跨并封闭这些结合位点。因此，C-末端必须重新定位以允许受体结合和随后的gD与调节复合物gH/gL的相互作用。我们之前构建了一个二硫键（K190 C/A277 C）蛋白，将C-末端锁定到gD核心。重要的是，这种突变蛋白结合受体，但未能触发融合，有效地分离受体结合和gH/gL相互作用。在这里，我们表明，通过还原二硫键“解锁”gD不仅恢复了gH/gL相互作用，但融合活性，以及，确认的C-末端运动在触发融合级联的重要性。我们对这些变化进行了表征，表明通过解锁暴露的C-末端区域是：（1）gH/gL结合位点;（2）包含一组（竞争社区）单克隆抗体（Mab）的表位，这些单克隆抗体（Mab）阻断gH/gL与gD的结合和细胞-细胞融合。在这里，我们产生了14个突变的gD C-末端内，以确定与gH/gL的相互作用和融合中涉及的关键构象变化的重要残基。作为一个实例，我们发现gDL 268 N是抗原正确的，因为它结合大多数Mab，但在融合中受损，表现出MC 14（阻断gD-gH/gL相互作用和融合的Mab）的受损结合，并且不能结合截短的gH/gL，所有事件都与C末端移动的抑制有关。我们的结论是，在C-末端，残基268是必不可少的gH/gL的结合和诱导的构象变化，并作为一个灵活的拐点，在关键的运动的gD C-末端。
Herpes simplex virus (HSV) requires four essential virion glycoproteins—gD, gH, gL, and gB—for virus entry and cell fusion. To initiate fusion, the receptor binding protein gD interacts with one of two major cell receptors, HVEM or nectin-1. Once gD binds to a receptor, fusion is carried out by the gH/gL heterodimer and gB. A comparison of free and receptor-bound gD crystal structures revealed that receptor binding domains are located within residues in the N-terminus and core of gD. Problematically, the C-terminus lies across and occludes these binding sites. Consequentially, the C-terminus must relocate to allow for both receptor binding and the subsequent gD interaction with the regulatory complex gH/gL. We previously constructed a disulfide bonded (K190C/A277C) protein that locked the C-terminus to the gD core. Importantly, this mutant protein bound receptor but failed to trigger fusion, effectively separating receptor binding and gH/gL interaction. Here, we show that “unlocking” gD by reducing the disulfide bond restored not only gH/gL interaction but fusion activity as well, confirming the importance of C-terminal movement in triggering the fusion cascade. We characterize these changes, showing that the C-terminus region exposed by unlocking is: (1) a gH/gL binding site; (2) contains epitopes for a group (competition community) of monoclonal antibodies (Mabs) that block gH/gL binding to gD and cell–cell fusion. Here, we generated 14 mutations within the gD C-terminus to identify residues important for the interaction with gH/gL and the key conformational changes involved in fusion. As one example, we found that gD L268N was antigenically correct in that it bound most Mabs but was impaired in fusion, exhibited compromised binding of MC14 (a Mab that blocks both gD–gH/gL interaction and fusion), and failed to bind truncated gH/gL, all events that are associated with the inhibition of C-terminus movement. We conclude that, within the C-terminus, residue 268 is essential for gH/gL binding and induction of conformational changes and serves as a flexible inflection point in the critical movement of the gD C-terminus.
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影响因子：
6.7
作者：
Di Giovine P;Settembre EC;Bhargava AK;Luftig MA;Lou H;Cohen GH;Eisenberg RJ;Krummenacher C;Carfi A
通讯作者：
Carfi A
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16
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5.4
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通讯作者：
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影响因子：
5.4
作者：
Cairns, Tina M.;Friedman, Lisa S.;Eisenberg, Roselyn J.
通讯作者：
Eisenberg, Roselyn J.