Mutations in the SARS CoV2 Spike Gene and Their Reflections on the Spike Protein

Objective: In this study, it was aimed to determine the mutation frequency in spike (S) genes of SARS CoV2 from six different regions of the world, their distribution on the gene and reflections of these mutations to the S protein. Methods: SARS CoV2 S gene sequences originating from Asia, Africa, Europe, South America, Oceania and North America were obtained from NCBI virus database. The sequences were analyzed with Geneious and BioEdit multiple sequence alignment programs. Results:865 distinct mutations on the S genes were detected in the virus samples. Among these, 59 variants with numbers of 10 and above in the virus population were detected. The D614G(A1841G) substitution was found to be the most common with an average of 88.6%. Furthermore, it was determined that 5477N(G1430A) substitution in the viruses of Oceania differed from other regions with a rate of 86.7%. The average mutation frequency of the S genes from different regions was calculated as 3,93x10(5). Conclusion: The significant differences among the mutation frequencies in SARS CoV2 S genes isolated from different regions was identified. At least five distinct amino acid substitutions with high ratios in the population were detected in the RBD domain, which is involved in the binding of the viruses to the ACE2 receptor. These substitutions are T1355G (L452R), G1430A (5477N), C1433A (T478K), G1450A (E484K) and A1501T (N501Y). Among these, the S477N is the most predominant in the population. However, the importance of these mutations needs to be demonstrated both in silico and experimental studies.