Molecular dynamics simulations of the Spike trimeric ectodomain of the SARS-CoV-2 Omicron variant: structural relationships with infectivity, evasion to immune system and transmissibility

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant is replacing Delta, the most prevalent variant worldwide from the beginning of 2021 until early 2022. The Omicron variant is highly transmissible and responsible for a new worldwide COVID-19 wave. Herein, we calculated molecular dynamics simulations of the SARS-CoV-2 trimeric spike protein of Wuhan-Hu-1 strain (wild type, WT) and the Omicron variant of concern. Structural analyses reveal that the SpikeOmicron presents more conformational flexibility than SpikeWT, mainly in the N-terminal domain (NTD) and receptor-binding domain (RBD). Such flexibility results in a broader spectrum of different conformations for SpikeOmicron, whereby the RBD can more easily visit an up-conformational state. We reported how the mutations in this variant may influence the intra- and inter-protomer contacts caused by conformational flexibility of the NTD. Based on our analysis, we suggest that the differences in conformational flexibility between SpikeOmicron and SpikeWT may explain the observed gains in infectivity, immune system evasion and transmissibility in this novel variant. Graphical abstract O_FIG_DISPLAY_L [Figure 1] M_FIG_DISPLAY C_FIG_DISPLAY