Mechanistic insights into Zika virus NS3 helicase inhibition by Epigallocatechin-3-gallate: Supplementary Files

Deepak Kumar; Nitin Sharma; Murali Aarthy; Sanjeev Singh; Rajanish Giri

Recently, a mutational study has shown that residues THR 201, ARG2 02, and GLU 286 are critical for NTP hydrolysis by ZIKV NS3 helicase (31) . Also, a compound NITD008 was shown to inhibit ZIKV replication experimentally where mechanism was elucidated computationally to show binding at the NTPase site with significant interactions at P-loop region (36) . Based upon computational findings, we have done inhibition assays where EGCG has shown significant dose dependent inhibition of NTPase activity with IC50 of 295.7 nM by Malachite green method. Further, the mode of inhibition was determined to be uncompetitive with inhibition constant (K i ) in low micromolar range (K i = 0.387 ± 0.034 µM). A study of polyphenols inhibiting ZIKV protease has shown that EGCG inhibits protease with higher IC50 (87 µM) values (37) . Taken together, our findings suggest that EGCG may target ZIKV helicase more specifically in addition to envelope protein and NS3 protease.