Physicochemical effects of emerging exchanges on the spike protein's RBM of the SARS-CoV-2 Omicron subvariants BA.1-BA.5 and its influence on the biological properties and attributes developed by these subvariants.

Emerging in South Africa, SARS-CoV-2 Omicron variant was marked by the expression of an exaggerated number of mutations throughout its genome and by the emergence of subvariants, whose attributes developed by them have been associated with amino acid exchanges that occur mainly in the RBM region of the spike protein. The RBM comprises a region within the RBD and is directly involved in the SARS-CoV-2 spike protein interaction with the host cell ACE2 receptor, during the infection mechanism and viral transmission. Defined as the region from aa 437 to aa 508, there are several residues in certain positions that interact directly with the human ACE-2 receptor during these processes. The occurrence of amino acid exchanges in these positions causes physicochemical alterations in the SARS-CoV-2 spike protein, which confer additional advantages and attributes to the agent. In addition, these exchanges serve as a basis for the characterization of new variants and subvariants of SARS-CoV-2. In this review, the amino acid exchanges that have occurred in the RBM of the subvariants BA.1 to BA.5 of SARS-CoV-2 that emerged from the Omicron are described. The physicochemical effects caused by them on spike protein are also described, as well as their influence on the biological properties and attributes developed by the subvariants BA.1, BA.2, BA.3, BA.4 and BA.5.