INHIBITION OF HIV-1 REV-RRE INTERACTION BY DIPHENYLFURAN DERIVATIVES

The interactions between RNA structures, such as RRE in the HIV-1 geno me, and proteins, such as Rev of HIV-1, are essential for efficient vi ral replication. Compounds that bind specifically to such RNAs and dis rupt their protein complexes offer a novel mechanism for inhibition of replication of the virus. As a step in this approach, we have designe d and characterized a series of synthetic diphenylfuran cations that s electively inhibit Rev binding to RRE. Fluorescence titrations and gel band-shift results indicate that the diphenylfurans bind to RRE and i nhibit Rev complex formation in a structure-dependent manner. The deri vative with the greatest affinity for RRE has an association constant of greater than 10(7) M(-1) and inhibits formation of the Rev-RRE comp lex at concentrations below 1 mu M. It binds to RRE considerably more strongly than it binds to simple RNA duplexes. Spectral. changes and e nergy transfer results on complex formation suggest that the compound has a nonclassical intercalation binding mode. CD studies with modifie d RRE hairpins indicate that the active diphenylfurans bind at the str uctured internal loop of RRE and cause a conformational change. The mo st active diphenylfurans are tetracations that appear to bind to RRE b y a threading intercalation mode and cause a conformational change in the RNA that is essential for inhibition of Rev complex formation with RRE.