Dark Proteome of Newly Emerged SARS-CoV-2 in Comparison with Human and Bat Coronaviruses

Rajanish Giri; Taniya Bhardwaj; Meenakshi Shegane; Bhuvaneshwari R. Gehi; Prateek Kumar; Kundlik Gadhave

Replicase polyprotein 1ab. The longer replicase polyprotein 1ab is a 7,073 amino acid-long polypeptide, which contains 15 non-structural proteins listed in Table 3 . Nsp1, Nsp2, and Nsp3 are cleaved using a viral papain-like proteinase (Nsp3/PL-Pro), while the rest of Nsps are cleaved by another viral 3C-like proteinase, Nsp5/3CL-Pro. We mapped the cleavage sites of the replicase 1ab polyprotein from Human SARS CoV to the disorder profile of this polyprotein. Figure 18 represents the results of this analysis by showing zoomed-in regions surrounding all the cleavage sites with few residues spanning at both terminals. Interestingly, we observed that all the cleavage sites are largely disordered, suggesting that intrinsic disorder may have a crucial role in the maturation of individual non-structural proteins. As the Nsps of Human SARS CoV are evolutionary close to the Nsps of SARS-CoV-2, we hypothesize that the cleavage sites in the SARS-CoV-2 replicase 1ab polyprotein are also intrinsically disordered or flexible. To shed more light on other implications of IDPRs, the structural and functional properties of Nsps and their predicted IDPRs are thoroughly described below. author/funder. All rights reserved. No reuse allowed without permission.