Interaction of La (III) and Tb (III) ions with purine nucleotides: evidence for metal chelation (N-7-M-PO3) and the effect of macrochelate formation on the nucleotide sugar conformation.
The interaction of the La (III) and Tb (III) ions with adenosine-5'-monophosphate (5'-AMP), guanosine-5'-monophosphate (5'-GMP), and 2'-deoxyguanosine-5'-monophosphate (5'-dGMP) anions with metal/nucleotide ratios of 1 and 2 has been studied in aqueous solution in acidic and neutral pHs. The solid complexes were isolated and characterized by Fourier transform ir and 1H-nmr spectroscopy. The lanthanide (III)-nucleotide complexes are polymeric in nature both in the solid and aqueous solutions. In the metal-nucleotide complexes isolated from acidic solution, the nucleotide binding is via the phosphate group (inner sphere) and an indirect metal-N-7 interaction (outer-sphere) with the adenine N-1 site protonated. In the complexes obtained from neutral solution, metal chelation through the N-7 and the PO3(2-) group is prevailing. In aqueous solution, an equilibrium between the inner and outer sphere metal-nucleotide interaction has been observed. The ribose moiety shows C2'-endo/anti pucker in the free AMP anion and in the lanthanide (III)-AMP complexes, whereas the GMP anion with C2'-endo/anti sugar conformation exhibits a mixture of the C2'-endo/anti and C3'-endo/anti sugar puckers in the lanthanide (III)-GMP salts. The deoxyribose has O4'-endo/anti sugar pucker in the free dGMP anion and a C3'-endo/anti, in the lanthanide (III)-dGMP complexes.
Tajmir-Riahi
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Centre de recherche en photobiophysique, Université du Québec à Trois-Rivières, Canada.
D000249:Adenosine Monophosphate / Q000737:chemistry; D002241:Carbohydrates / Q000737:chemistry*; D002614:Chelating Agents / Q000737:chemistry; D003848:Deoxyguanine Nucleotides / Q000737:chemistry; D005583:Fourier Analysis; D006157:Guanosine Monophosphate / Q000737:chemistry; D007811:Lanthanum / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008674:Metals, Rare Earth / Q000737:chemistry; D008968:Molecular Conformation; D011685:Purine Nucleotides / Q000737:chemistry*; D012996:Solutions; D013725:Terbium / Q000737:chemistry*
D002241:Carbohydrates; D002614:Chelating Agents; D003848:Deoxyguanine Nucleotides; D008674:Metals, Rare Earth; D011685:Purine Nucleotides; D012996:Solutions; D013725:Terbium; D000249:Adenosine Monophosphate; D007811:Lanthanum; C007257:2'-deoxyguanosine 5'-phosphate; D006157:Guanosine Monophosphate