¹⁷O NMR Spectral Properties of Simple Phosphate Esters and Adenine Nucleotides

The ¹⁷O NMR chemical shifts and one-bond ³¹P—¹⁷O coupling constants of the phosphoryl oxygens in inorganic phosphate, methyl phosphate, dimethyl phosphate, trimethyl phosphate, inorganic thiophosphate, AMP, ADP, and ATP have been measured at 95 °C in 20% D₂O as solvent. The chemical shifts of the resonances of the weakly acidic phosphoryl oxygens of these compounds are dependent on pH at 30 °C, with protonation of the oxygen anions leading to upfield shifts; the magnitude of the charge on the phosphoryl oxygen appears to be an important factor in determining the chemical shift of the associated resonance. An evaluation of the temperature dependence of the line widths of several of the labeled compounds suggests that ¹⁷O NMR spectroscopy may be able to provide useful information about the electronic structure and molecular motion of phosphate esters.