Molecular Investigations of Selected Spike Protein Mutations in SARS-CoV-2: Delta and Omicron Variants and Omicron Subvariants

Among the multiple SARS-CoV-2 variants recently reported, the Delta variant has generated most perilous and widespread effects. Another variant, Omicron, has been identified specifically for its high transmissibility. Omicron contains numerous spike (S) protein mutations and in numbers much larger than those of its predecessor variants. In this report we discuss some essential structural aspects and time-based structure changes of a selected set of spike protein mutations within the Delta and Omicron variants. The expected impact of multiple-point mutations within the spike protein’s receptor-binding domain (RBD) and S1 of these variants are examined. Additionally, RBD of the more recently emerged subvariants BA.4, BA.5 and BA.2.12.1 are discussed. Within the latter group, BA.5 represents globally, the most prevalent form of SARS-CoV-2 at the present time. Temporal mutation profile for the subvariant BF.7 and currently circulating variants of interest (VOI) and variants under monitoring (VUMs) including XBB.1.5, BQ.1, BA.2.75, CH.1.1, XBB and XBF are computationally explored here briefly with the expectation that these structural data will be helpful to identify drug targets and to neutralize antibodies for the evolving variants/subvariants of SARS-CoV-2.