The known cleavage sites of the DV polyprotein by NS2B/NS3pro are well established and the substrate models in this study were built based on the sequence alignment reported by Niyomrattanakit et al. [27]. Functional substrate profiling of the P1–P5 and P1′–P5′ regions of the proteases has been described previously for all four DV serotypes and revealed that the four enzymes appear to share very similar substrate specificities [27]. The sequence of each substrate model was generally composed of 10 amino acid residues containing the proteolytic site as well as important residues that were reported to interact with the protease active site, as shown in Fig. 1. The protease cleavage sites for the substrates are known to occur at P2P1↓P1′, which the P1 and P2 sites are two basic residues (R or K) and a short side-chain amino acid (G, S or A) is at the P1′ site (Fig. 1).