Binding of Nucleotide Inhibitors to the NS5 RdRp of the ZIKA Virus in the Replication Initiation State.

Abstract

The bindings of several ribonucleoside triphosphate (NTP) inhibitors to the RNA-dependent RNA polymerase (RdRp) of the Zika virus (ZIKV) are studied herein to identify potential drug-like candidates that can inhibit the replication of the viral genome by RdRp. In this study, a guanosine triphosphate (GTP) bound RdRp structure is generated to model the replication initiation state of RdRp. Subsequently, the bindings of 30 NTP inhibitors to the GTP binding site of RdRp are studied in detail by using the molecular docking method. Based on the docking scores, four NTP inhibitors, such as 2'-Cmethyl- adenosine-5'-triphosphate (mATP), 7-deaza-2'-C-methyladenosine-TP (daza-- mATP), 1-N6-Ethenoadenosine-5'-triphosphate (eATP), and Remdesivir-5'-triphosphate (RTP) are shortlisted for further analysis by employing molecular dynamics simulations and binding free-energy methods. These inhibitors are found to bind to RdRp quite strongly, as evident from their relative binding free energies that lie between -31.54±4.54 to -89.46±4.58 kcal/- mol. As the binding of RTP to the GTP site of RdRp generates the most stable complex, which is about 45 kcal/mol more stable than the binding of GTP to RdRp, it is most likely that RTP may inhibit the replication of the Zika viral genome efficiently. However, experimental studies are required to measure the potency of RTP and other drugs before their clinical use.