SOME NOVEL FLUORESCENT AZO COMPOUNDS AS INTERCALATORS FOR CALF THYMUS DNA

DNA-ligand interaction has been characterized by intercalation, groove-binding or electrostatic interaction l -4. Ability of some sequences to recognize DNA double helices by chemical modification of DNA or inhibition of DNA binding protein or by triple helix formation via Hoogsteen base pairing has been utilized in c1eavage,8. However, several aspects including DNA sequence and structural specificity, chemical structure and biological activity relationships and the nature of site exclusion still remain largely unclear. The changes induced in the electronic absorption spectra and fluorescence characteri stics of ligands upon intercalation have been efficiently used to determine the kinetics of ligand-DNA system. and al so evidenced by earlier reports from our laboratory on intercalation of substituted naphthalimide with CT-DNA, supercoiled pBR 322 plasmid and synthetic polynucleotides ll ,12.