17O NMR investigation of the hydration of L-alanine and L-proline in water/Me2SO mixtures.
The hydration state of L-Alanine and L-Proline has been assessed via 17O NMR. At neutral and basic pH, two water molecules are hydrogen bonded at the carboxylate group, one to each oxygen, whereas a third water molecule is hydrogen bonded to the protonated COOH group at acidic pH, via the hydroxyl hydrogen. The possible formation of dimers and/or higher complexes in DMSO is indicated not only from the chemical shift but also from the linewidth of the amino acids.
D000409:Alanine / Q000032:analysis*; D004121:Dimethyl Sulfoxide; D006860:Hydrogen Bonding; D006863:Hydrogen-Ion Concentration; D009682:Magnetic Resonance Spectroscopy; D010103:Oxygen Isotopes; D011392:Proline / Q000032:analysis*; D014867:Water
D010103:Oxygen Isotopes; D014867:Water; D011392:Proline; D000409:Alanine; D004121:Dimethyl Sulfoxide