Identification and Characterization of Zika Virus NS5 Methyltransferase Inhibitors

Abstract

The recurring outbreak of Zika virus (ZIKV) worldwide makes an emergent demand for novel, safe and efficacious anti-ZIKV agents. ZIKV non-structural protein 5 (NS5) methyltransferase (MTase), which is essential for viral replication, is regarded as a potential drug target. In our study, a luminescence-based methyltransferase assay was used to establish the ZIKV NS5 MTase inhibitor screening model. Through screening a natural product library, we found theaflavin, a polyphenol derived from tea, could inhibit ZIKV NS5 MTase activity with a 50% inhibitory concentration (IC50) of 10.10 μM. Molecular docking and site-directed mutagenesis analyses identified D146 as the key amino acid in the interaction between ZIKV NS5 MTase and theaflavin. The SPR assay indicated that theaflavin had a stronger binding activity with ZIKV NS5 wild-type (WT)-MTase than it with D146A-MTase. Moreover, theaflavin exhibited a dose dependent inhibitory effect on ZIKV replication with a 50% effective concentration (EC50) of 8.19 μM. All these results indicate that theaflavin is likely to be a promising lead compound against ZIKV.

Chemoinformatic Design and Profiling of Derivatives of Dasabuvir, Efavirenz, and Tipranavir as Potential Inhibitors of Zika Virus RNA-Dependent RNA Polymerase and Methyltransferase

“…This study observed intermolecular interactions between Phe133, Arg160, and Arg163 in the methyltransferase with the designed compounds (Figures and ). Other compounds like theaflavin, a natural compound, have been reported to directly bind to Asp146 of zika virus NS5 MTase to inhibit replication . Asp146 in zika virus is part of the Lys61–Asp146–Lys182–Glu218 tetrad motif that is important for both N-7 and 2′O methylation, and the designed compounds ( 3d , 5d , 16d , 17d , 3t , 10t , 22t to 26t ) showed interaction with Asp146 (Figures a–c, , a–c, and S2 in Supporting Information 3).…”

“…Previous studies have reported inhibitors of the zika virus replication/NS5-RNA-dependent RNA polymerase and/or NS5-methyltransferase ,,− ,,, using various strategies. This study identified some derivatives of the said parent compounds as potential inhibitors of the virus NS5 protein, and a previous report had validated N -[4-[6- tert -butyl-5-methoxy-8-(6-methoxy-2-oxo-1 H -pyridin-3-yl)-3 quinolyl] phenyl] methanesulfonamide (PubChem identifier: CID 49835560), a derivative of dasabuvir, against hepatitis C virus NS5B polymerase but not zika virus.…”

“…However, 1e showed equivalent binding energy of −6.675 ± 0.05 kcal/mol and K i of 12.67519392 ± 1.115312 μM for RNA-dependent RNA polymerase, while 4e showed equivalent binding energy of −7.6 ± 0.00 kcal/mol and K i of 2.648363028 ± 0.000000 μM for NS5-methyltransferase when compared with efavirenz, 3e, (−6.60 ± 0.00 kcal/mol and 14.34816176 ± 0.000000 μM for RNA-dependent RNA polymerase; −7.43 ± 0.05 kcal/mol and 3.568824547 ± 0.288630 μM for NS5-methyltransferase) (Supporting Information 1). Previous studies have reported inhibitors of the zika virus replication/NS5-RNA-dependent RNA polymerase and/or NS5-methyltransferase 2,13,[15][16][17][18][19]36,47,48 using various strategies. This study identified some derivatives of the said parent compounds as potential inhibitors of the virus NS5 protein, and a previous report had validated N- [4-[6-tert-butyl-5methoxy-8-(6-methoxy-2-oxo-1H-pyridin-3-yl)-3 quinolyl] phenyl] methanesulfonamide (PubChem identifier: CID 49835560), a derivative of dasabuvir, against hepatitis C virus NS5B polymerase 44 but not zika virus.…”

“…Other compounds like theaflavin, a natural compound, have been reported to directly bind to Asp146 of zika virus NS5 MTase to inhibit replication. 48 Asp146 in zika virus is part of the Lys61− Asp146−Lys182−Glu218 tetrad motif that is important for both N-7 and 2′O methylation, 51 and the designed compounds (3d, 5d, 16d, 17d, 3t, 10t, 22t to 26t) showed interaction with Asp146 (Figures 2a−c, 4, 5a−c, and S2 in Supporting Information 3). This implies that the designed derivatives of dasabuvir and tipranavir are possible inhibitors of methylation at the N-7 position, which is essential for viral replication and methylation at the 2′-O position and helps the virus evade the host immune response.…”

Discovery of Bispecific Lead Compounds From Azadirachta Indica Against ZIKA NS2B-NS3 Protease and RNA Dependent RNA Polymerase Using Molecular Simulations

“…In addition, NS5 protein also carries methyltransferase activity at the N-terminal end, which is required for the 5' capping of newly synthesized viral mRNA [43]. Hence, in the last five years after the WHO announced the ZIKV outbreak with a global health emergency in 2016, various orthosteric inhibitors [44,45], allosteric inhibitors [46][47][48], ZIKV pro inhibitors [49][50][51], ZIKV RdRp inhibitors [52][53][54][55], and a few inhibitors with unknown molecular targets [56][57][58] were screened and tested against ZIKV infection. However, only one compound, viz.…”