Inversion of DNA helicity induced by zinc (II)-macrocyclic polyamine complexes |
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| Authors: | Mitsuhiko Shionoya Eiichi Kimura Hiromi Hayashida Gabor Petho Luigi G Marzilli |
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| Institution: | 1. Department of Medicinal Chemistry , School of Medicine, Hiroshima University , Minami-ku, Kasumi 1-2-3, Hiroshima, 734, Japan;2. Department of Chemistry , Emory University , Atlanta, Georgia, 30322, USA |
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| Abstract: | Abstract Exposure of synthetic polynucleotide poly(dG-dC)·poly(dG-dC) to ZnII cyclen, 2 (cyclen = 1,4,7,10-tetraazacyclododecane), produces a dramatic change in its circular dichroism (CD) spectrum in H2O at pH 7.2, 24°C: the CD spectrum of the initial B form changes to that of the Z form (or a non-Z structure with a left-handed helix) at very low concentrations (ZnII]/base pair] in molar basis ≤ 1). By contrast, ZnII-12]aneN3, 1 (12]aneN3 = 1,5,9-triazacyclododecane), and ZnII-cyclam, 3 (cyclam = 1,4,8,11-tetraazacyclo-tetradecane), do not significantly have such a topological affect on the polynucleotide even at much higher concentrations. An increase in Na+ ionic strength nullified the effect of 2 on the CD spectrum, indicating an outside interaction (electrostatic and/or hydrogen bonding) of the DNA model. This study illustrates the significance of the macrocyclic ligand structure around the ZnII ion for specific interaction with DNA. |
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