Organisation of the orthobunyavirus tripodal spike and the structural changes induced by low pH and K + during entry
Organisation of the orthobunyavirus tripodal spike and the structural changes induced by low pH and K + during entry
复制标题
正布尼亚病毒三足刺突的组织以及进入过程中低 pH 和 K 诱导的结构变化
DOI：
10.1101/2022.08.11.503604
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Hover S
中科院分区：
文献类型：
--
作者：
Hover S
内吞作用后，有包膜病毒利用成熟内体不断变化的环境作为促进内体逃逸的线索，这一过程通常由病毒糖蛋白介导。我们之前表明，高 [K+] 和低 pH 值都会促进布尼亚姆维拉病毒 (BUNV)（典型的布尼亚病毒）的进入。在这里，我们使用子断层图平均和 AlphaFold 来生成整个 BUNV 糖蛋白包膜的伪原子模型。我们明确地将 Gc 融合域及其伴侣 Gn 定位在尖峰的底域内。此外，病毒在低 pH 值和高 [K+] 条件下孵育（类似于内吞条件），会导致 BUNV 包膜发生戏剧性的重排。结构和生化分析表明，在没有靶膜的情况下，pH 6.3/K+ 会引发 BUNV GP 的融合能力触发中间状态；但当目标膜存在时，相同的条件会诱导融合。综上所述，我们提供了对布尼亚病毒进入要求的机制理解。
Following endocytosis, enveloped viruses employ the changing environment of maturing endosomes as cues to promote endosomal escape, a process often mediated by viral glycoproteins. We previously showed that both high [K+] and low pH promote entry of Bunyamwera virus (BUNV), the prototypical bunyavirus. Here, we use sub-tomogram averaging and AlphaFold, to generate a pseudo-atomic model of the whole BUNV glycoprotein envelope. We unambiguously locate the Gc fusion domain and its chaperone Gn within the floor domain of the spike. Furthermore, viral incubation at low pH and high [K+], reminiscent of endocytic conditions, results in a dramatic rearrangement of the BUNV envelope. Structural and biochemical assays indicate that pH 6.3/K+in the absence of a target membrane elicits a fusion-capable triggered intermediate state of BUNV GPs; but the same conditions induce fusion when target membranes are present. Taken together, we provide mechanistic understanding of the requirements for bunyavirus entry.