Mutations Observed in the SARS-CoV-2 Spike Glycoprotein and Their Effects in the Interaction of Virus with ACE-2 Receptor

Coronaviruses (CoVs) classified in the Coronaviridae family infect a very large spectrum of vertebrate group. Seven CoVs that cause human disease consist of Alpha-CoVs, which are HCoV-229E, and NL63 and beta-CoVs, which are MERS-CoV, SARS-CoV, HCoV-OC43, HCoV-HKU1, and SARS-CoV-2. SARS-CoV-2 is an enveloped, positive-polarity, single-stranded RNA virus responsible for a new Coronavirus disease 2019 (COVID-19). The mutagenic ability of the SARS-CoV-2 directs its evolution and genome variability, thus allowing viruses to escape from host immunity and develop drug resistance. Tracing viral mutations is also important for the development of new vaccines, antiviral drugs, and diagnostic systems. During replication in the host cell, genomic mutations occur in the virus and these mutations are transferred to new generations. For this reason, systematic monitoring of mutations in the SARS-CoV-2 genome allows observation of the national and international molecular epidemiology of the virus. SARS-CoV-2 spike (S) glycoprotein is vital in the binding of the virus to the host cell receptor that is angiotensin converting-enzyme 2 (ACE2), membrane fusion, vaccine studies and immune response to the virus. Therefore, mutations in the gene encoding the S glycoprotein and especially the possible variations in the receptor binding domain (RBD) in S gene are important issues to be emphasized. In this article, information about the mutations observed in the SARS-CoV-2 S glycoprotein and their possible effects are presented.