RESUMEN
Among the current five Variants of Concern, infections caused by the SARS-CoV-2 B.1.617.2 (Delta) variant are often associated with the greatest severity. Despite recent advances on the molecular basis of elevated pathogenicity using recombinant proteins, architecture of intact Delta virions remains veiled. Moreover, molecular evidences for the detailed mechanism of S-mediated membrane fusion are missing. Here we reported the in situ structure and distribution of S on the authentic Delta variant, and discovered invagination in the distinctive Delta architecture. We also captured fusion snapshots from the virus-virus fusion events, provided structural evidences for Deltas attenuated dependency on cellular factors for fusion activation, and proposed a model of S-mediated membrane fusion. Site-specific glycan analysis revealed increased oligomannose-type glycosylation of native Delta S over that of the Wuhan-Hu-1 S. Together, these results disclose distinctive factors of Delta being the most virulent SARS-CoV-2 variant. In BriefCryo-ET of intact SARS-CoV-2 Delta variant revealed its distinctive architecture and captured snapshots of its membrane fusion in action.
RESUMEN
Since the outbreak of COVID-19 caused by the 2019-nCoV (SARS-CoV-2), with its high pathogenicity and contagiousness, it has posed a serious threat to global public health security. Up to now, the pathogenesis of 2019-nCoV is unclear, and there is no effective treatment. Vaccine as one of the most effective strategies to prevent virus infection has become a hot area. Based on the current understanding of 2019-nCoV, the development of 2019-nCoV vaccines covers all types: inactivated virus vaccine, recombinant protein vaccine, viral vector-based vaccine, mRNA vaccine, and DNA vaccine, etc. In this review, we focus on the candidate targets of the novel coronavirus, and the types, development status and progress of 2019-nCoV vaccines in order to provide information for further research and prevention.
RESUMEN
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is an enveloped virus responsible for the COVID-19 pandemic. Despite recent advances in the structural elucidation of SARS-CoV-2 proteins and the complexes of the spike (S) proteins with the cellular receptor ACE2 or neutralizing antibodies, detailed architecture of the intact virus remains to be unveiled. Here we report the molecular assembly of the authentic SARS-CoV-2 virus using cryo-electron tomography (cryo-ET) and subtomogram averaging (STA). Native structures of the S proteins in both pre- and postfusion conformations were determined to average resolutions of 8.7-11 [A]. Compositions of the N-linked glycans from the native spikes were analyzed by mass-spectrometry, which revealed highly similar overall processing states of the native glycans to that of the recombinant glycoprotein glycans. The native conformation of the ribonucleoproteins (RNP) and its higher-order assemblies were revealed. Overall, these characterizations have revealed the architecture of the SARS-CoV-2 virus in unprecedented detail, and shed lights on how the virus packs its [~]30 kb long single-segmented RNA in the [~]80 nm diameter lumen.
