Header

UZH-Logo

Maintenance Infos

Metal-Ion-Coordinating Properties of the Dinucleotide 2′-Deoxyguanylyl(5′→3′)-2′-deoxy-5′-guanylate (d(pGpG)3−): Isomeric Equilibria Including Macrochelated Complexes Relevant for Nucleic Acids


Knobloch, B; Sigel, H; Okruszek, A; Sigel, Roland K O (2007). Metal-Ion-Coordinating Properties of the Dinucleotide 2′-Deoxyguanylyl(5′→3′)-2′-deoxy-5′-guanylate (d(pGpG)3−): Isomeric Equilibria Including Macrochelated Complexes Relevant for Nucleic Acids. Chemistry - A European Journal, 13(6):1804-1814.

Abstract

The interaction between divalent metal ions and nucleic acids is wellknown, yet knowledge about the intensity of these interactions at the various sites with labile metal ions is very scarce. Therefore we have studied by potentiometric pH titrations the stabilities of complexes formed between the nucleic acid model d(pGpG) and the essential metal ions Mg2+ and Zn2+ as well as with the toxic ions Cd2+ and Pb2+. A comparison of the present results with earlier data obtained for M(pUpU)– complexes allows the conclusion that phosphate-bound Mg2+ and Cd2+ form macrochelates via the interaction with N7, whereas the also phosphate-coordinated Pb2+ forms a 10-membered chelate with the neighboring phosphate diester bridge. Zn2+ forms both types of chelates with formation degrees of about 91% and 2.4% for and , respectively; the open form with Zn2+ bound only to the terminal phosphate group, , amounts to about 6.8%. The various intramolecular Equilibria have also been quantified for the other metal ions. Zn2+, Cu2+, and Cd2+ also form macrochelates in the monoprotonated M[H;d(pGpG)] species (the proton being at the terminal phosphate group), i.e., the metal ion at N7 interacts to some extent with the P(O)2(OH)– group. Thus, this study demonstrates that the coordinating properties of the various metal ions toward a pGpG unit in a nucleic acid differ individually: Mg2+, Zn2+, and Cd2+ have a significant tendency to bridge the distance between N7 and the phosphate group of a (d)GMP unit, though to various extents; whereas Pb2+ (and possibly Ca2+) prefer a pure phosphate coordination.

Abstract

The interaction between divalent metal ions and nucleic acids is wellknown, yet knowledge about the intensity of these interactions at the various sites with labile metal ions is very scarce. Therefore we have studied by potentiometric pH titrations the stabilities of complexes formed between the nucleic acid model d(pGpG) and the essential metal ions Mg2+ and Zn2+ as well as with the toxic ions Cd2+ and Pb2+. A comparison of the present results with earlier data obtained for M(pUpU)– complexes allows the conclusion that phosphate-bound Mg2+ and Cd2+ form macrochelates via the interaction with N7, whereas the also phosphate-coordinated Pb2+ forms a 10-membered chelate with the neighboring phosphate diester bridge. Zn2+ forms both types of chelates with formation degrees of about 91% and 2.4% for and , respectively; the open form with Zn2+ bound only to the terminal phosphate group, , amounts to about 6.8%. The various intramolecular Equilibria have also been quantified for the other metal ions. Zn2+, Cu2+, and Cd2+ also form macrochelates in the monoprotonated M[H;d(pGpG)] species (the proton being at the terminal phosphate group), i.e., the metal ion at N7 interacts to some extent with the P(O)2(OH)– group. Thus, this study demonstrates that the coordinating properties of the various metal ions toward a pGpG unit in a nucleic acid differ individually: Mg2+, Zn2+, and Cd2+ have a significant tendency to bridge the distance between N7 and the phosphate group of a (d)GMP unit, though to various extents; whereas Pb2+ (and possibly Ca2+) prefer a pure phosphate coordination.

Statistics

Citations

19 citations in Web of Science®
19 citations in Scopus®
Google Scholar™

Altmetrics

Downloads

0 downloads since deposited on 08 Aug 2013
0 downloads since 12 months

Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:07 Faculty of Science > Department of Chemistry
Dewey Decimal Classification:540 Chemistry
Language:English
Date:12 February 2007
Deposited On:08 Aug 2013 07:34
Last Modified:23 Nov 2017 05:20
Publisher:Wiley-VCH Verlag Berlin
ISSN:0947-6539
Publisher DOI:https://doi.org/10.1002/chem.200600744

Download