Molecular dynamics study on the effect of the N1 neuraminidase double mutant G147R/H274Y on oseltamivir sensitivity.

Inhibition of neuraminidase is the most prominent target in influenza medication using oseltamivir as an inhibitor. However, the emerging resistance of neuraminidase toward oseltamivir due to mutation reduces the efficacy of oseltamivir. The generally reported mutation is a single mutation at H274Y, which declines the sensitivity of oseltamivir by almost 900 folds compared to the wild-type variant. Moreover, an additional mutation at G147R increases the resistance by more than 2000 folds. However, sufficient studies on the resistance mechanism of this variant have not yet been reported. Therefore, we simulated four neuraminidase proteins comprising wild-type (WT), G147R, H274Y, and G147R/H274Y using molecular dynamics simulation to disclose the binding mechanism of oseltamivir. Trajectory analysis was conducted to reveal structural stability and flexibility. Furthermore, end-point free binding energy calculations were conducted. The energy decomposition of each residue was also calculated. The end-point energy calculation showed a similar result to that of experimental data. The energy decomposition analysis revealed that G147R/H274Y showed significant reduction in oseltamivir (OST) interaction with R118. Salt-bridge disruption caused by R224-E276 was also observed. Modification to enhance the polarity of the inhibitor might be useful in overcoming these changes. However, it should be noted that such changes could worsen the pharmacokinetic property of the inhibitor. It is hoped that these findings will provide useful insights for the development of an anti-influenza drug that can withstand the mutant variant.