Emerging novel coronavirus (2019-nCoV)—current scenario, evolutionary perspective based on genome analysis and recent developments

Malik, Yashpal Singh; Sircar, Shubhankar; Bhat, Sudipta; Sharun, Khan; Dhama, Kuldeep; Dadar, Maryam; Tiwari, Ruchi; Chaicumpa, Wanpen

In the genomic analysis, the S gene of 2019-nCoVs was found to exhibit lower sequence identity with other Betacoronaviruses. Difference in spike protein encoded by 2019-nCoV compared with the Bat SARS-like CoVs, SARS-CoV, and MERS-CoV is depicted in Figure 5 . The length of 'S' protein of nCoV is longer (1282 amino acids) than other two viruses (SARS-1255 amino acid and BatSL-1246 amino acids) under the same Sarbecovirus subgenus. The 'S' protein of nCoV has been detected with three short insertions at the N-terminal region, along with four changes in the receptor binding motif inside the receptor binding domain in comparison with SARS-CoV (Zhou et al. 2020) . Several previous studies have shown the usage of different receptors for CoVs like human ACE2 for SARS-CoV and CD26 for MERS-CoV . Identical motifs and residues to that of SARS-CoVs have been identified in the nCoV, yet they show divergence based on phylogeny (Letko and Munster 2020) . A recent finding proves that the binding capacity of nCoV 'S' protein with human ACE2 is as efficient as SARS-CoV, which further promotes the human-to-human transmission (Letko and Munster 2020).