PREDICTABILITY OF DESIGNING SPECIFIC BINDING INTERACTIONS FOR DNA MINOR-GROOVE LIGANDS FROM NMR-SPECTROSCOPY AND MOLECULAR MODELING - A COPPER(II)-ACTIVATED DNA CLEAVER BASED ON HOECHST-33258

Analogs of Hoechst 33258 have been designed and synthesized to incorpo rate a 3,4-catecholic or a 3,4,5-trihydroxyphenyl function in place of the 4-phenolic group of the template molecule, Molecular design was b ased on the three-dimensional models of the solution structures of Hoe chst 33258 and its nz-hydroxy isomer which had been derived from high- field NMR spectroscopic analysis, The predicted solution structure of the catecholic analog as its minor groove complex with duplex d(CGCGAA TTCGCG)(2) was confirmed by direct high-resolution NMR spectroscopy co mbined with molecular dynamics, using NMR-derived distance restraints. While the 3,4-catecholic analog was unable to cleave DNA in the prese nce of Cu(II) ions, the 3,4,5-trihydroxyphenyl analog of Hoechst 33258 was found to be an effective cleaver of DNA at low concentration when activated by copper(lI) ions, a difference ascribed to the inaccessib ility for copper chelation of the 3,4-dihydroxy site in its minor groo ve complex with DNA.