Abstract
The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron is currently the most prevalent SARS-CoV-2 variant worldwide. Herein, we calculated molecular dynamics simulations of the trimeric spikeWT and SpikeBA.1 for 300 ns. Our results show that SpikeBA.1 has more conformational flexibility than SpikeWT. Our principal component analysis (PCA) allowed us to observe a broader spectrum of different conformations for SpikeBA.1, mainly at N-terminal domain (NTD) and receptor-binding domain (RBD). Such increased flexibility could contribute to decreased neutralizing antibody recognition of this variant. Our molecular dynamics data show that the RBDBA.1 easily visits an up-conformational state and the prevalent D614G mutation is pivotal to explain molecular dynamics results for this variant because to lost hydrogen bonding interactions between the residue pairs K854SC/D614SC, Y837MC/D614MC, K835SC/D614SC, T859SC/D614SC. In addition, SpikeBA.1 residues near the furin cleavage site are more flexible than in SpikeWT, probably due to P681H and D614G substitutions. Finally, dynamical cross-correlation matrix (DCCM) analysis reveals that D614G and P681H may allosterically affect the cleavage site S1/S2. Conversely, S2' site may be influenced by residues located between NTD and RBD of a neighboring protomer of the SpikeWT. Such communication may be lost in SpikeBA.1, explaining the changes of the cell tropism in the viral infection. In addition, the movements of the NTDWT and NTDBA.1 may modulate the RBD conformation through allosteric effects. Taken together, our results explain how the structural aspects may explain the observed gains in infectivity, immune system evasion and transmissibility of the Omicron variant.
Communicated by Ramaswamy H. Sarma
Acknowledgments
The authors acknowledge the National Council for Scientific and Technological Development (CNPq), the Coordination for the Improvement of Higher Education Personnel (CAPES, grant 88887.374931/2019-00, Coordenação de Aperfeiçoamento de Pessoal de Nível Superior—Finance Code 01), and the São Paulo Research Foundation (FAPESP, grants 2019/00195-2, 2020/04680-0, 2016/09047-8), Rede Virus MCTI (grant FINEP 0459/20), Brazil, for financial support. The authors also acknowledge Geoambiente Sensoriamento Remoto LTDA for their generous support and for providing access to the Google Cloud services supported by grant FAPESP 2021/00070-5.
Disclosure statement
The authors declare no conflict of interest.