An alternative HIV-1 non-nucleoside Reverse Transcriptase inhibition mechanism: Targeting the p51 subunit

HIV drug resistance continues to demand for alternative drug targets. Since Reverse Transcriptase (RT) is unique and critical for the virus life cycle, it is a rational target that is likely to have less off-target effects in humans. Serendipitously, we found two chemical compound scaffolds from the NCI Diversity Set V that inhibited the HIV1- RT catalytic activity. Computational structural analyses and subsequent experimental testing demonstrated that one of the two chemical scaffolds binds to a novel location in the HIV-1 RT p51 subunit, interacting with residue Y183 that has no known association with previously reported drug resistance. This finding leads to the notion of a novel druggable site on p51 for a new class of non-nucleoside RT Inhibitors that may inhibit HIV-1 RT allosterically. Although inhibitory activity was shown experimentally only to be in the hundreds micromolar range, the scaffolds serve as a proof-of-concept of targeting HIV RT p51, with the possibility for medical chemistry methods to be applied to improve the inhibitory activity, towards a functioning drug.