一论文标题：Structural basis for enhanced infectivity and immune evasion of SARS-CoV-2 variants
作者：Yongfei Cai , Jun Zhang , Tianshu Xiao , Christy L. Lavine , Shaun Rawson , Hanqin Peng , Haisun Zhu , Krishna Anand , Pei Tong , Avneesh Gautam , Shen Lu , Sarah M. Sterling , Richard M. Walsh Jr., Sophia Rits-Volloch , Jianming Lu , Duane R. Wesemann , Wei Yang , Michael S. Seaman , Bing Chen
期刊：Science
发表时间：2021/06/24
数字识别码：10.1126/science.abi9745
摘要：Several fast-spreading variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have become the dominant circulating strains in the COVID-19 pandemic. We report here cryo-EM structures of the full-length spike (S) trimers of the B.1.1.7 and B.1.351 variants, as well as their biochemical and antigenic properties. Amino acid substitutions in the B.1.1.7 protein increase the accessibility of its receptor binding domain and also the binding affinity for receptor angiotensin-converting enzyme 2 (ACE2). The enhanced receptor engagement may account for the increased transmissibility. The B.1.351 variant has evolved to reshape antigenic surfaces of the major neutralizing sites on the S protein, making it resistant to some potent neutralizing antibodies. These findings provide structural details on how SARS-CoV-2 has evolved to enhance viral fitness and immune evasion.
所属学科：
病毒学
二论文标题：Structural impact on SARS-CoV-2 spike protein by D614G substitution
作者：Jun Zhang , Yongfei Cai , Tianshu Xiao , Jianming Lu , Hanqin Peng , Sarah M. Sterling , Richard M. Walsh Jr., Sophia Rits-Volloch , Haisun Zhu , Alec N. Woosley , Wei Yang , Piotr Sliz , Bing Chen
期刊：Science
发表时间：2021/04/30
数字识别码：10.1126/science.abf2303
摘要：Substitution for aspartic acid (D) by glycine (G) at position 614 in the spike (S) protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) appears to facilitate rapid viral spread. The G614 strain and its recent variants are now the dominant circulating forms. Here, we report cryo–electron microscopy structures of a full-length G614 S trimer, which adopts three distinct prefusion conformations that differ primarily by the position of one receptor-binding domain. A loop disordered in the D614 S trimer wedges between domains within a protomer in the G614 spike. This added interaction appears to prevent premature dissociation of the G614 trimer—effectively increasing the number of functional spikes and enhancing infectivity—and to modulate structural rearrangements for membrane fusion. These findings extend our understanding of viral entry and suggest an improved immunogen for vaccine development.
