The SARS-CoV-2 spike protein: balancing stability and infectivity.
The SARS-CoV-2 spike protein: balancing stability and infectivity.
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DOI：
10.1038/s41422-020-00430-4
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发表时间：
2020-12
期刊：
影响因子：
44.1
通讯作者：
Schaffitzel C
中科院分区：
文献类型：
--
作者：
Berger I;Schaffitzel C
SARS-CoV-2刺突（S）糖蛋白是目前对抗COVID-19疫苗开发工作的关键目标;中和抗体结合S并干扰S与其受体血管紧张素转换酶2的结合。最近的工作揭示了全球流行的D 614 G S突变增加传染性的分子基础。SARS-CoV-2大流行是一场全球危机，在全球范围内造成无数死亡和经济损失，大大超过了2002-2004年的SARS-CoV爆发。SARS-CoV-2 S糖蛋白被切割成S1和S2亚基，使病毒和宿主细胞膜融合。与SARS-CoV S相比，SARS-CoV-2 S对血管紧张素转换酶2（ACE 2）具有更高的亲和力，这是由于受体结合基序（RBM）中的六个突变。1，2此外，SARS-CoV-2 S在S1和S2之间获得了一个弗林蛋白酶切割位点（图1），被认为是促进致病性的。3ACE 2结合触发构象变化，允许宿主蛋白酶进一步切割S2，随后S1脱落并激活剧烈的S2重折叠成融合后状态。4在冷冻电镜和功能研究中，采用不同的策略稳定融合前SARS-CoV-2S三聚体：突变或缺失弗林蛋白酶切割位点，S2中的两个脯氨酸（2 P）突变（K986 P，V987 P）和C端三聚体结构域，其取代了野生型S的跨膜结构域和胞质C端。1，2确定了大量的S结构，揭示了一种高度动态的蛋白质：S受体结合结构域（RBD）经历铰链样运动，在“向下”和“向上”构象之间切换;“向上”与ACE 2结合相容，而RBM则隐藏在“向下”构象中。在冷冻EM样品中观察到50%-70%的S开放构象（RBD向上-向下-向下），沿着30%-50%的封闭三聚体（RBD全部向下），认为开放形式介导感染性。1，2具有天然弗林蛋白酶位点的S的结构，通过2 P突变稳定，突出了切割3的影响：虽然在未切割形式中约83%的S处于闭合构象，但在弗林蛋白酶切割的S中仅34%闭合。其余粒子采用中间（一个RBD无序）和开放构象（上-下-下）。总之，弗林蛋白酶切割促进S1 RBD和N-末端结构域（NTD）的移动，导致较低的热稳定性和更多的受体结合活性形式的S。
SARS-CoV-2 spike (S) glycoprotein is the key target of current vaccine development efforts to combat COVID-19; neutralizing antibodies bind S and interfere with S binding to its receptor, angiotensin-converting enzyme 2. Recent work reveals the molecular basis of increased infectivity of the globally prevailing D614G S mutation.The SARS-CoV-2 pandemic is a global crisis causing countless deaths and economic damage worldwide, vastly surpassing the previous SARS-CoV outbreak in 2002–2004. SARS-CoV-2 S glycoprotein is cleaved into S1 and S2 subunits enabling fusion of virus and host cell membranes. SARS-CoV-2 S has higher affinity for angiotensin-converting enzyme 2 (ACE2) as compared to SARS-CoV S due to six mutations in the receptor-binding motif (RBM). 1, 2 Moreover, SARS-CoV-2 S acquired a furin cleavage site between S1 and S2 (Fig. 1), thought to promote pathogenecity. 3 ACE2 binding triggers conformational changes that allow host proteases to further cleave S2, followed by shedding of S1 and activation of drastic S2 refolding into a post-fusion state. 4 For cryo-EM and functional studies, different strategies were followed to stabilize the prefusion SARS-CoV-2 S trimer: mutation or deletion of the furin cleavage site, two proline (2P) mutations in S2 (K986P, V987P) and a C-terminal trimerization domain which replaces the transmembrane domain and cytoplasmic C-terminus of wild-type S. 1, 2 Numerous S structures were determined, revealing a highly dynamic protein: S receptor-binding domains (RBDs) undergo hinge-like movements to switch between “down” and “up” conformations;“up” is compatible with ACE2 binding while the RBM is tucked away in the “down” conformation. 50%–70% open conformations (RBDs up-down-down) were observed for S, along with 30%–50% closed trimer (RBDs all-down) in cryo-EM samples, with the open form thought to mediate infectivity. 1, 2 The structure of S with a native furin site, stabilized by the 2P mutation, highlighted the impact of cleavage 3: while in the uncleaved form~ 83% of S were in a closed conformation, only 34% were closed in furin-cleaved S. The remaining particles adopted intermediate (one RBD disordered) and open conformations (up-down-down). Overall, furin cleavage facilitates the movement of S1 RBDs and N-terminal domains (NTDs), leading to lower thermal stability and more receptor bindingcompetent forms of S.
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DOI：
10.1126/science.abd3255
发表时间：
2020-11-06
期刊：
Science (New York, N.Y.)
影响因子：
--
作者：
Toelzer C;Gupta K;Yadav SKN;Borucu U;Davidson AD;Kavanagh Williamson M;Shoemark DK;Garzoni F;Staufer O;Milligan R;Capin J;Mulholland AJ;Spatz J;Fitzgerald D;Berger I;Schaffitzel C
通讯作者：
Schaffitzel C
影响因子：
16.8
作者：
Wrobel AG;Benton DJ;Xu P;Roustan C;Martin SR;Rosenthal PB;Skehel JJ;Gamblin SJ
通讯作者：
Gamblin SJ
影响因子：
16.8
作者：
Henderson R;Edwards RJ;Mansouri K;Janowska K;Stalls V;Gobeil SMC;Kopp M;Li D;Parks R;Hsu AL;Borgnia MJ;Haynes BF;Acharya P
通讯作者：
Acharya P
影响因子：
64.5
作者：
Yurkovetskiy, Leonid;Wang, Xue;Luban, Jeremy
通讯作者：
Luban, Jeremy
影响因子：
56.9
作者：
Cai, Yongfei;Zhang, Jun;Chen, Bing
通讯作者：
Chen, Bing