A New Generation of Peptide-based Inhibitors Targeting HIV-1 Reverse Transcriptase Conformational Flexibility

The biologically active form of human immunodeficiency virus (HIV) type 1 reverse transcriptase (RT) is a heterodimer. The formation of RT is a two-step mechanism, including a rapid protein-protein interaction "the dimerization step,"followed by conformational changes "the maturation step,"yielding the biologically active form of the enzyme. We have previously proposed that the heterodimeric organization of RT constitutes an interesting target for the design of new inhibitors. Here, we propose a new class of RT inhibitors that targets protein-protein interactions and conformational changes involved in the maturation of heterodimeric reverse transcriptase. Based on a screen of peptides derived from the thumb domain of this enzyme, we have identified a short peptide PAW that inhibits the maturation step and blocks viral replication at subnano-molar concentrations. PAW only binds dimeric RT and stabilizes it in an inactive/non-processive conformation. From a mechanistic point of view, PAW prevents proper binding of primer/template by affecting the structural dynamics of the thumb/fingers of p66 subunit. Taken together, these results demonstrate that HIV-1 RT maturation constitutes an attractive target for AIDS chemotherapeutics.