1H NMR chemical shift study on the stacking interaction between purine and 6-methylpurine

✍ Scribed by Ferenc Aradi

• Publisher: John Wiley and Sons
• Year: 1990
• Tongue: English
• Weight: 398 KB
• Volume: 28
• Category: Article
• ISSN: 0749-1581
• DOI: 10.1002/mrc.1260281209

✦ Synopsis

Abstract

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.