Identification of the Fusion Peptide-Containing Region in Betacoronavirus Spike Glycoproteins
Identification of the Fusion Peptide-Containing Region in Betacoronavirus Spike Glycoproteins
复制标题
β冠状病毒刺突糖蛋白中含融合肽区域的鉴定。
DOI：
10.1128/jvi.00015-16
复制
发表时间：
2016-06-01
影响因子：
5.4
通讯作者：
Qian, Zhaohui
中科院分区：
文献类型：
--
作者：
Ou, Xiuyuan;Zheng, Wangliang;Qian, Zhaohui
融合肽（FP）在病毒包膜与细胞膜的融合中发挥着重要作用。不同冠状病毒 (CoV) 的刺突 (S) 糖蛋白中 FP 的位置和特性尚未确定。通过对代表性冠状病毒S蛋白的氨基酸序列分析，我们确定了一个共同区域作为可能的FP（pFP），它具有I类病毒融合蛋白FP的特征，包括高Ala/Gly含量、中等疏水性和少量带电残基。为了检验该区域包含 CoV FP 的假设，我们对中东呼吸综合征乙型冠状病毒 (MERS-CoV) 的 pFP 中的每个残基进行了系统突变，发现 pFP 中的 22 个残基中有 11 个（从 G953 到 L964，A956 除外）对于 S 蛋白介导的细胞间融合和病毒进入至关重要。合成的 MERS-CoV pFP 核心肽 ((955)IAGVGWTAGL(964)) 诱导脂质体膜的广泛融合，而突变肽未能诱导任何脂质混合。我们还选择性地突变了另外两种 β-CoV 的 pFP 残基，即严重急性呼吸综合征冠状病毒（SARS-CoV）和小鼠肝炎病毒（MHV）。尽管这两种 pFP 的氨基酸序列与 MERS-CoV 以及彼此之间存在显着差异，但 SARS-CoV 和 MHV 的大多数 pFP 突变体也未能介导膜融合，表明这些 pFP 也是功能性 FP。因此，3 种不同谱系的 β-CoV 的 FP 在 S 糖蛋白内的位置和功能是保守的，尽管它们的氨基酸序列在 CoV 进化过程中存在显着差异。 重要性 在许多包膜病毒的 I 类病毒融合蛋白中，FP 是病毒包膜与宿主细胞膜融合导致病毒感染的关键介质。来自病毒家族的 FP，如流感病毒或人类免疫缺陷病毒 (HIV)，往往具有较高的氨基酸序列同一性。在这项研究中，我们确定了 3 种 β-CoV、MERS-CoV、SARS-CoV 和 MHV 的 S 糖蛋白 FP 的位置和氨基酸序列，并证明它们对于介导细胞-细胞融合和病毒进入至关重要。有趣的是，与流感和 HIV 的 FP 形成鲜明对比，3 个不同谱系的 β-CoV 的 FP 的一级氨基酸序列存在显着差异。因此，在进化过程中，β-CoV 的 FP 在其一级序列上存在显着差异，同时保持相同的基本生物学功能。我们的研究结果确定了开发抗冠状病毒药物的潜在新靶点。
The fusion peptides (FP) play an essential role in fusion of viral envelope with cellular membranes. The location and properties of the FPs in the spike (S) glycoproteins of different coronaviruses (CoV) have not yet been determined. Through amino acid sequence analysis of S proteins of representative CoVs, we identified a common region as a possible FP (pFP) that shares the characteristics of FPs of class I viral fusion proteins, including high Ala/Gly content, intermediate hydrophobicity, and few charged residues. To test the hypothesis that this region contains the CoV FP, we systemically mutated every residue in the pFP of Middle East respiratory syndrome betacoronavirus (MERS-CoV) and found that 11 of the 22 residues in the pFP (from G953 to L964, except for A956) were essential for S protein-mediated cell-cell fusion and virus entry. The synthetic MERS-CoV pFP core peptide ((955)IAGVGWTAGL(964)) induced extensive fusion of liposome membranes, while mutant peptide failed to induce any lipid mixing. We also selectively mutated residues in pFPs of two other beta-CoVs, severe acute respiratory syndrome coronavirus (SARS-CoV) and mouse hepatitis virus (MHV). Although the amino acid sequences of these two pFPs differed significantly from that of MERS-CoV and each other, most of the pFP mutants of SARS-CoV and MHV also failed to mediate membrane fusion, suggesting that these pFPs are also the functional FPs. Thus, the FPs of 3 different lineages of beta-CoVs are conserved in location within the S glycoproteins and in their functions, although their amino acid sequences have diverged significantly during CoV evolution.IMPORTANCE Within the class I viral fusion proteins of many enveloped viruses, the FP is the critical mediator of fusion of the viral envelope with host cell membranes leading to virus infection. FPs from within a virus family, like influenza viruses or human immunodeficiency viruses ( HIV), tend to share high amino acid sequence identity. In this study, we determined the location and amino acid sequences of the FPs of S glycoproteins of 3 beta-CoVs, MERS-CoV, SARS-CoV, and MHV, and demonstrated that they were essential for mediating cell-cell fusion and virus entry. Interestingly, in marked contrast to the FPs of influenza and HIV, the primary amino acid sequences of the FPs of beta-CoVs in 3 different lineages differed significantly. Thus, during evolution the FPs of beta-CoVs have diverged significantly in their primary sequences while maintaining the same essential biological functions. Our findings identify a potential new target for development of drugs against CoVs.