By correlating the hydrogen bond interaction at each subsite of the substrates with the corresponding NS2B/NS3pro pocket (Table 1), the decomposition energies (DCs; the interaction energy of individual NS2B/NS3pro residues with the substrate and vice versa) were plotted (Fig. 5). At subsite P1, residue R was able to bind very well, as was residue K, in the DV2 NS2B/NS3pro, where the interaction between the P1(R) subsite with the S1 pocket of all systems was around −18 kcal mol−1 (except for 2B/3) and around −12 kcal mol−1(3/4A) in the case of P1(K). This result also implies that the S1 pocket of NS2B/NS3pro is rather specific for charged residues, such as R or K. Comparison of the pair interaction at the other substrate subsites with the NS2B/NS3pro protein pocket concluded that the preference of the interaction between the P2 subsite with the S2 pocket is R > K > Q; between the P3 subsite with the S3 pocket is R/Q/T > K/G, and no attractive interaction occurs between the P4 and P5 subsites with the S4 and S5 pockets. Note that only these P1–P3subsites were considered for the relative interaction because the non-prime site are more important than the prime site for interacting with the NS2B/NS3pro, as discussed before. These theoretically derived results broadly agree with the reported experimental data [39] that the preference of each subsite for interacting with NS2B/NS3pro are R > K, R > T > Q/N/K, K > R > N and Nle > L > K for P1, P2, P3 and P4, respectively.