SYNTHESIS AND BIOLOGICAL-ACTIVITIES OF FLUORESCENT ACRIDINE-CONTAINING HIV-1 NUCLEOCAPSID PROTEINS FOR INVESTIGATION OF NUCLEIC ACID-NCP7 INTERACTIONS

Specific interactions between the 72-amino acid nucleocapsid protein N Cp7 of the human immunodeficiency virus, type 1 and the genomic RNA ar e essential for virus replication. Studies on the mechanism of action of NCp7 require a direct visualization of its complexes with nucleic a cids and the determination of binding affinities. To facilitate these investigations, fluorescent NCp7 derivatives were developed by introdu ction in the NCp7 sequence of a non-natural amino acid, (S)-beta-(9-ac ridinyl)alanine (Aca) obtained by a chiral synthetic method. Three flu orescent NCp7 derivatives were obtained by introducing this amino acid at different positions. As shown by NMR, the three-dimensional struct ure of NCp7 is not altered by introduction of Aca. The fluorescent pep tides were found to be as potent as their precursors in interacting wi th nucleic acids and in promoting HIV-1 genomic RNA dimerization. More over, because of their fluorescent properties, these NCp7s can be used at submicromolar concentrations to directly visualize and quantify pr otein-nucleic acid interactions in solution or after gel electrophores is. This could facilitate the development of new antiviral agents aime d at inhibiting the functions of NCp7 and studies on the intracellular traffic of NCp7 within the preintegration complex. (C) Munksgaard 199 7.