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1 H NMR chemical shift study on the stacking interaction between purine and 6‐methylpurine
Author(s) -
Aradi Ferenc
Publication year - 1990
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.1260281209
Subject(s) - chemistry , stacking , chemical shift , dimer , purine , purine metabolism , nucleic acid , stereochemistry , decomposition , crystallography , computational chemistry , organic chemistry , biochemistry , enzyme
Mutually induced proton chemical shift changes were measured for purine‐6‐methylpurine solutions in deuterium oxide at 35° C. The chemical shift vs. concentration profiles were analysed using a three‐state decomposition model based on simultaneous, competitive dimer equilibria. The association parameters for purine‐6‐methylpurine hetero‐association provide some additional information about the effect of methylation on the stacking interaction between nucleic acid bases. The equilibrium constant (2.54 ± 0.17 and 2.57 ± 0.29 I mol −1 , calculated from the experimental data on purine and 6‐methylpurine, respectively) suggests the dominant role of the methylated counterpart in the association. The upfield dimer shifts indicate that the methyl group perturbs the plane‐to‐plane or stacking‐like arrangement in the associated state.