Linear heptapeptides containing DNA-intercalators. Synthesis and interaction with DNA

Five peptides of general structure X-Ser-Pro-Thr-Ser-Pro-Ser-Y (X = Tyr, qu inoxaline-2-carbonyl, acridine-9-carbonyl, Y = Tyr, (quinoxalin-2-yl)amino) were prepared using standard solid-phase peptide synthesis technique. Thei r interaction with DNA (calf thymus DNA and plasmids pUC9, p Delta NS and p GEMEX) was studied using UV and CD spectroscopy, sedi mentation analysis an d agarose gel electrophoresis after treatment with topoisomerase I. In cont rast to earlier findings (Suzuki M.: Nature 1990, 344, 562) intercalation i nto DNA structure has not been proved for any compound studied.