INTERACTION OF DISTAMYCIN A AND NETROPSIN WITH QUADRUPLEX AND DUPLEX STRUCTURES: A COMPARATIVE H-NMR STUDY (original) (raw)

2002, Nucleosides Nucleotides & Nucleic Acids

Homonuclear NMR techniques have been used to investigate the interactions of the minor groove binding agents distamycin A (Dist-A) and the related drug netropsin (Net) with three quadruplexes characterized by different groove widths: [d(TGGGGT)] 4 (Q1), [d(GGGGTTTTGGGG)] 2 (Q2), and d(GGGGTTGGGGTGTGGGGTTGGGG) (Q3). Netropsin has been found to be in a fast chemical exchange with all three kinds of quadruplexes, whereas Dist-A interacts tightly with Q1 and, at a less extent, with Q2. In order to determine the degree of selectivity of Dist-A for two-rather than four-stranded DNA, we titrated with Dist-A an equimolar solution of Q1 and the duplex d(CGCAAATTTGCG) 2 (D). This comparative 1 H-NMR study allowed us to conclude that Dist-A and, consequently, Net possess higher affinity for duplex DNA. *Corresponding