RESUMO
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants with multiple spike mutations enable increased transmission and antibody resistance. We combined cryo-electron microscopy (cryo-EM), binding, and computational analyses to study variant spikes, including one that was involved in transmission between minks and humans, and others that originated and spread in human populations. All variants showed increased angiotensin-converting enzyme 2 (ACE2) receptor binding and increased propensity for receptor binding domain (RBD)-up states. While adaptation to mink resulted in spike destabilization, the B.1.1.7 (UK) spike balanced stabilizing and destabilizing mutations. A local destabilizing effect of the RBD E484K mutation was implicated in resistance of the B.1.1.28/P.1 (Brazil) and B.1.351 (South Africa) variants to neutralizing antibodies. Our studies revealed allosteric effects of mutations and mechanistic differences that drive either interspecies transmission or escape from antibody neutralization.
Assuntos
SARS-CoV-2/química , SARS-CoV-2/genética , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/genética , Substituição de Aminoácidos , Enzima de Conversão de Angiotensina 2/metabolismo , Animais , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Antígenos Virais/imunologia , COVID-19/transmissão , COVID-19/veterinária , COVID-19/virologia , Microscopia Crioeletrônica , Adaptação ao Hospedeiro , Humanos , Evasão da Resposta Imune , Vison/virologia , Modelos Moleculares , Mutação , Ligação Proteica , Conformação Proteica , Domínios e Motivos de Interação entre Proteínas , Estrutura Quaternária de Proteína , Subunidades Proteicas/química , Receptores de Coronavírus/metabolismo , SARS-CoV-2/imunologia , Glicoproteína da Espícula de Coronavírus/imunologia , Glicoproteína da Espícula de Coronavírus/metabolismoRESUMO
New SARS-CoV-2 variants that have accumulated multiple mutations in the spike (S) glycoprotein enable increased transmission and resistance to neutralizing antibodies. Here, we study the antigenic and structural impacts of the S protein mutations from four variants, one that was involved in transmission between minks and humans, and three that rapidly spread in human populations and originated in the United Kingdom, Brazil or South Africa. All variants either retained or improved binding to the ACE2 receptor. The B.1.1.7 (UK) and B.1.1.28 (Brazil) spike variants showed reduced binding to neutralizing NTD and RBD antibodies, respectively, while the B.1.351 (SA) variant showed reduced binding to both NTD- and RBD-directed antibodies. Cryo-EM structural analyses revealed allosteric effects of the mutations on spike conformations and revealed mechanistic differences that either drive inter-species transmission or promotes viral escape from dominant neutralizing epitopes. HIGHLIGHTS: Cryo-EM structures reveal changes in SARS-CoV-2 S protein during inter-species transmission or immune evasion.Adaptation to mink resulted in increased ACE2 binding and spike destabilization.B.1.1.7 S mutations reveal an intricate balance of stabilizing and destabilizing effects that impact receptor and antibody binding.E484K mutation in B.1.351 and B.1.1.28 S proteins drives immune evasion by altering RBD conformation.S protein uses different mechanisms to converge upon similar solutions for altering RBD up/down positioning.
RESUMO
The severe acute respiratory coronavirus 2 (SARS-CoV-2) spike (S) protein is the target of vaccine design efforts to end the coronavirus disease 2019 (COVID-19) pandemic. Despite a low mutation rate, isolates with the D614G substitution in the S protein appeared early during the pandemic and are now the dominant form worldwide. Here, we explore S conformational changes and the effects of the D614G mutation on a soluble S ectodomain construct. Cryoelectron microscopy (cryo-EM) structures reveal altered receptor binding domain (RBD) disposition; antigenicity and proteolysis experiments reveal structural changes and enhanced furin cleavage efficiency of the G614 variant. Furthermore, furin cleavage alters the up/down ratio of the RBDs in the G614 S ectodomain, demonstrating an allosteric effect on RBD positioning triggered by changes in the SD2 region, which harbors residue 614 and the furin cleavage site. Our results elucidate SARS-CoV-2 S conformational landscape and allostery and have implications for vaccine design.
Assuntos
Peptídeo Hidrolases/metabolismo , SARS-CoV-2/metabolismo , Glicoproteína da Espícula de Coronavírus/metabolismo , COVID-19/patologia , COVID-19/virologia , Microscopia Crioeletrônica , Humanos , Imunogenicidade da Vacina , Simulação de Dinâmica Molecular , Mutação , Domínios Proteicos , Estabilidade Proteica , Estrutura Quaternária de Proteína , Subunidades Proteicas/metabolismo , Proteólise , SARS-CoV-2/isolamento & purificação , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/genéticaRESUMO
AIM: To evaluate the female oncofertility attitude and knowledge of reproductive health professionals in China. METHODS: An online survey was distributed to reproductive health professionals in Shanghai, China. RESULTS: Female professionals were more likely to consider that cancer patients would want to preserve their fertility. Participants with higher educational background tended to have a more positive attitude toward oncofertility. The majority of the participants (71.0%) obtained a fair or low level of oncofertility knowledge, and only 25.3% of them received scores at the 'good knowledge' level. CONCLUSION: There are significant gaps in the current oncofertility knowledge among reproductive health professionals in China, suggesting an urgent, unmet need for establishing an interdisciplinary fertility preservation training and service system.