Inhibitors of HIV integrase (IN) are being developed as potential anti-AIDS drugs. One class of lead structure currently under investigation can be broadly characterized as being of the aryl beta-diketo family. Members of this class have been reported independently to exhibit potent inhibition of HIV integrase in extracellular enzyme assays and to provide good antiviral effects in HIV-infected cells. Through the systematic design and synthesis of a large number of aryl beta-diketo analogues, we have developed novel azido containing aryl beta-diketo variants, which exhibit high IN inhibitory potency in extracellular assays and provide antiviral effects cells with reduced cytotoxicity in HIV infected. Recent work has focused on replacement of the beta-diketo portion of our azido containing inhibitors with the naphthyridine pharmacophore, which has shown utility in other clinically-relevant HIV-1 integrase inhibitors. In order to elucidate the manner in which these and other inhibitors interact with IN DNA substrate complexes, chemical and photo-activatable affinity labels have been incorporated into high affinity inhibitors. We have also developed the first members of a novel, new class of pharmacological tool that function as """"""""affinity acetylators"""""""" by site-specific acetylation of amino acid residues in the IN enzyme. Mass spectral studies are currently ongoing to elucidate sites of covalent attachment by these agents following incubation with the enzyme. Recent studies have examined the reactivities and selectivities towards the nucleophilic side chains of various amino acids of these affinity acetylators as compared with other alkylating functionalities. Based on differential reactivities, a new class of ?bifunctional? affinity ligands is being developed that may have applicability in the study of a broad range protein-ligand interactions. In separate studies, collaborative efforts are underway to obtain X ray structures of inhibitors bound to the HIV integrase enzyme. Information obtained from such X-ray structures should provide a starting point for the computer-assisted design of potent new inhibitors.
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