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Issue 39, 2008
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Effect of the riboseversus2′-deoxyribose residue on the metal ion-binding properties of purine nucleotides

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Abstract

The interaction between metal ions and nucleotides is well characterized, as is their importance for metabolic processes, e.g. in the synthesis of nucleic acids. Hence, it is surprising to find that no detailed comparison is available of the metal ion-binding properties between nucleoside 5′-phosphates and 2′-deoxynucleoside 5′-phosphates. Therefore, we have measured here by potentiometric pH titrations the stabilities of several metal ion complexes formed with 2′-deoxyadenosine 5′-monophosphate (dAMP2−), 2′-deoxyadenosine 5′-diphosphate (dADP3−) and 2′-deoxyadenosine 5′-triphosphate (dATP4−). These results are compared with previous data measured under the same conditions and available in the literature for the adenosine 5′-phosphates, AMP2−, ADP3− and ATP4−, as well as guanosine 5′-monophosphate (GMP2−) and 2′-deoxyguanosine 5′-monophosphate (dGMP2−). Hence, in total four nucleotide pairs, GMP2−/dGMP2−, AMP2−/dAMP2−, ADP3−/dADP3− and ATP4−/dATP4− (= NP/dNP), could be compared for the four metal ions Mg2+, Ni2+, Cu2+ and Zn2+ (= M2+). The comparisons show that complex stability and extent of macrochelate formation between the phosphate-coordinated metal ion and N7 of the purine residue is very similar (or even identical) for the AMP2−/dAMP2− and ADP3−/dADP3− pairs. In the case of the complexes formed with ATP4−/dATP4− the 2′-deoxy complexes are somewhat more stable and show also a slightly enhanced tendency for macrochelate formation. This is different for guanine nucleotides: the stabilities of the M(dGMP) complexes are clearly higher, as are the formation degrees of their macrochelates, than is the case with the M(GMP) complexes. This enhanced complex stability and greater tendency to form macrochelates can be attributed to the enhanced basicity (ΔpKaca. 0.2) of N7 in the 2′-deoxy compound. These results allow general conclusions regarding nucleic acids to be made.

Graphical abstract: Effect of the riboseversus2′-deoxyribose residue on the metal ion-binding properties of purine nucleotides

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Article information


Submitted
08 Apr 2008
Accepted
18 Jun 2008
First published
26 Aug 2008

Dalton Trans., 2008, 5368-5377
Article type
Paper

Effect of the riboseversus2′-deoxyribose residue on the metal ion-binding properties of purine nucleotides

A. Mucha, B. Knobloch, M. Jeżowska-Bojczuk, H. Kozłowski and R. K. O. Sigel, Dalton Trans., 2008, 5368
DOI: 10.1039/B805911J

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