Mutation Interest in the Receptor-Binding Domain of Spike Protein of Severe Acute Respiratory Syndrome Coronavirus 2 in the Northwest of Iran

Background: The spike protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been undergoing variation. Most of the variants cause no concern for human health. Some others have had worse outcomes in terms of transmissibility, vaccination resistance, and, generally, the survival of patients infected with SARS-CoV-2. Objectives: This study investigated the mutation of interest in the receptor-binding domain (RBD) of SARS-CoV-2. Methods: Ribonucleic acid (RNA) was extracted from 40 swap samples. Next, the polymerase chain reaction (PCR) assay was carried out to detect the RBD. Investigation of SARS-COV-2 RBD was performed completely by phylogenetic and tree alignment. The multiple sequence alignment (MSA) of the biological sequence of RBD was created by BioEdit, Snap Gene, and MEGA software and was then compared to sequences of different variants of SARS-COV-2 in the GenBank (National Center for Biotechnology Information). The Influenza Surveillance and Response System (GSAID) was used to detect mutations in the RBD sequence. Results: Multiple sequence alignment (MSA) RBD domain showed that the RBD domain sequence obtained from the Iranian patients' highest identity by severe acute respiratory syndrome coronavirus 2 isolate MZ907347. Several mutations of interest, including A475V, L452R, V483A, and F490L, were detected in the RBD region. However, the dN/dS analysis detected positive selection in RBD regions. Conclusions: Amino acid changes in the surface protein can significantly alter the viral function and/or interactions with neutralizing antibodies. Most of the nucleotide changes in the spike gene reduce infectivity. The V503W and P521Q mutations reduce infectivity, the A522Q mutation increases sensitivity to neutralizing antibodies, and the H519T mutation decreases susceptibility to convalescent sera.