Covalently Targeted Highly Conserved Tyr318 to Improve the Drug Resistance Profiles of HIV-1 NNRTIs: A Proof-of-Concept Study

This study presents proof of concept for designing a novel HIV-1 covalent inhibitor targeting the highly conserved Tyr318 in the HIV-1 non-nucleoside reverse transcriptase inhibitors binding pocket to improve the drug resistance profiles. The target inhibitor <b>ZA-2</b> with a fluorosulfate warhead in the structure was found to be a potent inhibitor (EC₅₀ = 11-246 nM) against HIV-1 IIIB and a panel of NNRTIs-resistant strains, being far superior to those of NVP and EFV. Moreover, <b>ZA-2</b> was demonstrated with lower cytotoxicity (CC₅₀ = 125 µM). In the reverse transcriptase inhibitory assay, <b>ZA-2</b> exhibited an IC₅₀ value of 0.057 µM with the ELISA method, and the MALDI-TOF MS data demonstrated the covalent binding mode of <b>ZA-2</b> with the enzyme. Additionally, the molecular simulations have also demonstrated that compounds can form covalent binding to the Tyr318.