Direct measurement of the Mn(II) hydration state in metal complexes and metalloproteins through 17O NMR line widths.

ABSTRACT: Here we describe a simple method to estimate the inner-sphere hydration state of the Mn(II) ion in coordination complexes and metalloproteins. The line width of bulk H2(17)O is measured in the presence and absence of Mn(II) as a function of temperature, and transverse (17)O relaxivities are calculated. It is demonstrated that the maximum (17)O relaxivity is directly proportional to the number of inner-sphere water ligands (q). Using a combination of literature data and experimental data for 12 Mn(II) complexes, we show that this method provides accurate estimates of q with an uncertainty of ±0.2 water molecules. The method can be implemented on commercial NMR spectrometers working at fields of 7 T and higher. The hydration number can be obtained for micromolar Mn(II) concentrations. We sho

SUBMITTER: Gale EM 

PROVIDER: S-EPMC3864583 | biostudies-literature | 2013 Dec

REPOSITORIES: biostudies-literature