Acid−Base and Metal Ion Binding Properties of Guanylyl(3‘→5‘)guanosine (GpG-) and 2‘-Deoxyguanylyl(3‘→5‘)-2‘-deoxyguanosine [d(GpG)-] in Aqueous Solution
- 7 May 2003
- journal article
- research article
- Published by American Chemical Society (ACS) in Inorganic Chemistry
- Vol. 42 (11), 3475-3482
- https://doi.org/10.1021/ic020672l
Abstract
The acidity constants of guanylyl(3'-->5')guanosine (GpG(-)) and 2'-deoxyguanylyl(3'-->5')-2'-deoxyguanosine [d(GpG)(-)] for the deprotonation of their (N1)H sites were measured by potentiometric pH titrations in aqueous solution (25 degrees C; I = 0.1 M, NaNO(3)). The same method was used for the determination of the stability constants of the 1:1 complexes formed between Mg(2+), Ni(2+), or Cd(2+) (= M(2+)) and (GG-H)(2-), and in the case of Mg(2+) also of (GG-2H)(3-), where GG(-) = GpG(-) or d(GpG)(-). The stability constants of the M(GG)(+) complexes were estimated. The acidity constants of the H(dGuo)(+) and dGuo species (dGuo = 2'-deoxyguanosine) and the stability constants of the corresponding M(dGuo)(2+) and M(dGuo-H)(+) complexes were also measured. Comparison of these and related data allows the conclusion that N7 of the 5'G unit in GG(-) is somewhat more basic than the one in the 3'G moiety; the same holds for the (N1)(-) sites. On the basis of comparisons with the stability constants measured for the dGuo complexes, it is concluded that M(2+) binding of the GG dinucleoside monophosphates occurs predominantly in a mono-site fashion, meaning that macrochelate formation is not very pronounced. Indeed, it was a surprise to find that the stabilities of the complexes of dGuo or (dGuo-H)(-) and the corresponding ones derived from GG(-) are so similar. Consequently, it is suggested that in the M(GG)(+) and M(GG-H) complexes the metal ion is mainly located at N7 of the 5'G unit since this is the more basic site allowing also an outer-sphere interaction with the C6 carbonyl oxygen and because this coordination mode is also favorable for an electrostatic interaction with the negatively charged phosphodiester bridge. It is further suggested that Mg(2+) binding (which is rather weak compared to that of Ni(2+) and Cd(2+)) occurs mainly in an outer-sphere mode, and on the basis of the so-called Stability Ruler it is concluded that the binding properties of Zn(2+) to the GG species are similar to those of Ni(2+) and Cd(2+).Keywords
This publication has 36 references indexed in Scilit:
- Interaction of zinc ions with d(CGCAATTGCG) in a 2.9 Å resolution X-ray structureJBIC Journal of Biological Inorganic Chemistry, 2002
- Imprinting Structural Information from a GpG Ligand into the Configuration of a Chiral Diamine Ligand through Second-Sphere Communication in Platinum(II) ComplexesInorganic Chemistry, 2000
- Crystal structure of a lead-dependent ribozyme revealing metal binding sites relevant to catalysis.Nature Structural & Molecular Biology, 1999
- NMR Solution Structure of a DNA Dodecamer Duplex Containing a cis-Diammineplatinum(II) d(GpG) Intrastrand Cross-Link, the Major Adduct of the Anticancer Drug CisplatinBiochemistry, 1998
- Comparison of the Extent of Macrochelate Formation in Complexes of Divalent Metal Ions with Guanosine (GMP2-), Inosine (IMP2-), and Adenosine 5'-Monophosphate (AMP2-). The Crucial Role of N-7 Basicity in Metal Ion-Nucleic Base RecognitionJournal of the American Chemical Society, 1994
- Interactions of metal ions with nucleotides and nucleic acids and their constituentsChemical Society Reviews, 1993
- H8 chemical shifts in oligonucleotides cross‐linked at a GpG Sequence by cis‐Pt(NH3)22+: a clue to the adduct structureEuropean Journal of Biochemistry, 1992
- CisplatinAnnals of Internal Medicine, 1984
- Molecular electrostatic potential of the nucleic acidsQuarterly Reviews of Biophysics, 1981
- Determination of microscopic basic ionization constants of guanylyl-(3' .far. 5')-guanosine. Structure and optical properties of half-protonated guanylyl-(3' .far. 5')-guanosine and their modelsJournal of the American Chemical Society, 1975