Design, synthesis, molecular modeling and anti-HIV 1 integrase activity of a series of photoactivatable diketo acid-containing inhibitors as affinity probes

The diketo acid (DKA) class of HIV-1 integrase (IN) inhibitors is thought to function by chelating divalent
metal ions on the enzyme catalytic site.However, differences in mutations conferring resistance to various
DKA inhibitors suggest that multiple binding orientations may exist. In order to facilitate identification
of DKA binding sites, a series of photoactivable analogues of two potent DKAs was prepared as novel
photoaffinity probes. In cross-linking assays designed to measure disruption of substrate DNA binding,
the photoprobes behaved similarly to a reference DKA inhibitor. Molecular modeling studies suggest
that such photoprobes interact within the IN active site in a manner similar to that of the parent DKAs.
Analogues Ia-c are novel photoaffinity ligands useful in clarifying the HIV-1 binding interactions of DKA
inhibitors.