Hydrophobic, Polar and Hydrogen Bonding Based Drug-Receptor Interaction of Tetrahydroimidazobenzodiazepinones

Anti-HIV drug discovery has been increasingly focusing on HIV-1-RT (reverse transcriptase) as a potential therapeutic target. Tetrahydroimidazobenzodiazepinone (TIBO) belongs to non-nucleoside group of reverse transcriptase inhibitors (NNRTIs). A computational chemistry study has been performed on a series of tetrahydroimidazo-benzodiazepinones as HIV-1-NNRT inhibitors. Problem statement: In order to search out new drug of desired activity from the lead compounds, there was need to know the interaction of drugs with their receptor i.e., type of force(s) that have predominant role. Approach: Log P and SASA have been used for measurement of hydrophobic interaction, energy of protonation for measurement of most favorable hydrogen bond acceptor site, bond length and bond strain for measurement of strength of hydrogen bond formed between drug and receptor, atomic charges, ionization potential, electronegativity, E^‡n and E^‡m and their difference ΔE^‡nm for measurement of polar interaction. The 3D modeling and geometry optimization of the compounds and receptor amino acids have been done by semiempirical method with MOPAC2002 associated with CAChe software. Results: The study has shown that hydrophobic interaction is predominant and made major contribution, while hydrogen bonding and polar interactions help in proper orientation of the compound (or its functional groups) to make maximam interaction. Conclusion: In this study theoretical technique has been discussed by which new hypothetical HIV-1-NNRT inhibitors can be developed prior to their synthesis only by introducing effective hydrophobic substituents at specific sites.