The Investigation of Coordinated Water in Paramagnetic Metalloproteins through Nuclear Magnetic Resonance Spectroscopy

Abstract

Water molecules bound to metal ions in metalloproteins are rather common. If the metal ion is paramagnetic or if the native diamagnetic metal ion can be substituted by a paramagnetic ion, then the detection of water molecules and the investigation of their properties may be conveniently carried out through ¹H, ²H. and ¹⁷O NMR spectroscopy. The information which can be drawn from such an analysis is here critically discussed with reference to some typical metalloproteins. The importance of the electronic correlation times, as related to the geometry of the chromophore in high-spin cobalt(II) derivatives, is stressed. The acid-base properties of the coordinated water are also considered.