title: A proton magnetic resonance study of the effects of polyamine and divalent metal ions on diadenosine 5',5'''-P1,P4-tetraphosphate base stacking.
abstract: Complexation of putrescine, spermidine, spermine, and Mg2+ with diadenosine 5',5'''-P1,P4-tetraphosphate induces an upfield shift in the signals for the H-2 and H-8 protons. The upfield shifts in H-2 indicate that cation complexation enhances intramolecular adenine stacking interactions. The resonances for H-2 and H-8 of neutral analogs of 5',5'-dinucleotides appear farther upfield relative to the appropriate monomeric models than those for the corresponding dinucleotide; reduction of intra-chain phosphate repulsion is the origin of cation induced enhancement of diadenosine 5H,5'''-P1,P4-tetraphosphate base stacking.
mesh_terms: D000227:Adenine Nucleotides; D000241:Adenosine / Q000031:analogs & derivatives; D002413:Cations, Divalent; D015226:Dinucleoside Phosphates; D007700:Kinetics; D008274:Magnesium; D009682:Magnetic Resonance Spectroscopy; D011522:Protons; D011700:Putrescine; D013095:Spermidine; D013096:Spermine
chemical_list: D000227:Adenine Nucleotides; D002413:Cations, Divalent; D015226:Dinucleoside Phosphates; D011522:Protons; D013096:Spermine; C020733:diadenosine tetraphosphate; D008274:Magnesium; D000241:Adenosine; D013095:Spermidine; D011700:Putrescine