SARS-CoV-2 RdRp uses NDPs as a substrate and is able to incorporate NHC into RNA from diphosphate form molnupiravir

The coronavirus disease 2019 has been ravaging throughout the world for three years and has severely impaired both human health and the economy. The causative agent, severe acute respiratory syndrome coronavirus 2 employs the viral RNA dependent RNA polymerase (RdRp) complex for genome replication and transcription, making RdRp an appealing target for antiviral drug development. Systematic characterization of RdRp will undoubtedly aid in the development of antiviral drugs targeting RdRp. Here, our research reveals that RdRp can recognize and utilize nucleoside diphosphates as a substrate to synthesize RNA with an efficiency of about two thirds of using nucleoside triphosphates as a substrate. Nucleoside diphosphates incorporation is also template -specific and has high fidelity. Moreover, RdRp can incorporate beta-d-N4-hydroxycytidine into RNA while using diphosphate form molnupiravir as a substrate. This incorporation results in genome mutation and virus death. It is also observed that diphosphate form molnupiravir is a better substrate for RdRp than the triphosphate form molnupiravir, presenting a new strategy for drug design.

Automated summary

The coronavirus disease 2019 has caused significant harm to global health and economy for three years. Research on the viral RNA dependent RNA polymerase (RdRp) complex reveals its potential as a target for antiviral drug development. The study found that RdRp can efficiently synthesize RNA using nucleoside diphosphates as substrates and can incorporate molnupiravir diphosphate, leading to genome mutation and virus death. The diphosphate form of molnupiravir is shown to be a better substrate for RdRp than the triphosphate form, providing a new drug design strategy.