Rational Design of the Remdesivir Binding Site in the RNA-dependent RNA Polymerase of SARS-CoV-2: Implications for Potential Resistance

SARS-CoV-2 is rapidly evolving with the continuous emergence of new mutations. There is no specific antiviral therapy for COVID-19, and the use of Remdesivir for treating COVID-19 will likely continue before clinical trials are completed. Due to the lengthening pandemic and evolving nature of the virus, predicting potential residues prone to mutations is crucial for the management of Remdesivir resistance. We used a rational ligand-based interface design complemented with mutational mapping to generate a total of 100,000 mutations and provide insight into the functional outcome of mutations in the Remdesivir-binding site in nsp12. After designing 56 residues in the Remdesivir binding site of nsp12, the designs retained 96-98% sequence identity, which suggests that SARS-CoV-2 attains resistance and develops further infectivity with very few mutations in the nsp12. We also identified affinity-attenuating Remdesivir binding designs of nsp12. Several mutants acquired decreased binding affinity with Remdesivir, which suggested drug resistance. These hotspot residues had a higher probability of undergoing selective mutations in the future to develop Remdesivir and related drug-based resistance. A comparison of 21 nsp12 Remdesivir-bound designs to the 13 EIDD-2801-bound nsp12 designs suggested that EIDD-2801 would be more effective in preventing the emergence of resistant mutations and against Remdesivir-resistance strains due to the restricted mutational landscape. Combined with the availability of more genomic data, our information on mutation repertoires is critical to guide scientists to rational structure-based drug discovery. Knowledge of the potential residues prone to mutation improves our understanding and management of drug resistance and disease pathogenesis.