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

Finally, Table 2 shows that S protein from SARS-CoV-2 contain one MoRF region at its Cterminal (residues 1265-1272) by MoRFchibi_web, two MoRF regions ((residues 2-6) & (residues 819-823)) by MoRFPred, and one MoRF region at N-terminal (residues 1-10) by DISOPRED3. These results indicating that intrinsic disorder is important for its interaction with binding partners. Interestingly, the N-terminal region of S protein (residues 1-10) from all three viruses are observed to be a disorder-based protein binding region by two predictors (MoRFPred and DISOPRED3). N-terminal MoRF displays its role in viral interaction with host receptor and C-terminal MoRF displays its role in M protein interaction and viral assembly. Moreover, MoRF region mainly lies in the N-and C-terminal regions suggesting a possible role during cleavage as well. In addition to protein-binding regions, S protein also shows many nucleotide-binding residues. Tables 9, 10, and 11 shows that numerous RNA binding residues predicted by PPRint in all three viruses and a single RNA binding residue were predicted by DisoRDPbind in human SARS. Further, DRNApred and DisoRDPbind predicted the presence of many DNA binding residues in S protein of all three viruses. These results signify the role of S protein functions related to molecular recognition (protein-protein interaction, RNA binding, and DNA binding) such as interaction with host cell membrane and further viral infection. Therefore, identified IDPs/IDPRs and residues/regions from S protein crucial for molecular recognition can be targeted for disorder-based drug discovery.