1H/31P NMR techniques were applied to analyze the binding mode of guanosine 2'-monophosphate (2'-GMP) to histone. To date, no structures of the complex comprising 2'-GMP and histone have been deposited in Protein Data Bank. Because the 31P nucleus can be a selective marker of phosphorylated compounds, the combined use of 1H and 31P NMR spectroscopy has been applied to investigate these molecular interactions. The complex formation was initially confirmed by 31P-diffusion ordered spectroscopy and 31P-T1 measurements. In 1H{1H} saturation transfer difference experiments, H2' and H3' signals of 2'-GMP were significantly attenuated, while the rest of the unexchangeable protons were observed, indicating that the contribution of H2' and H3' to the binding epitopes was low. The WaterLOGSY-type experiment with 31P detection also indicated that a phosphorylated group located close to H2' and H3' had little access to histone.
Keywords: 31P NMR; Molecular interactions; guanosine 2′-monophosphate; histone.