Characterisation of protein unfolding by NMR diffusion measurements

The characterisation of non-native states of proteins is a key problem instudies of protein folding. Complete characterisation of these states requiresa description of both local and global properties, including moleculardimensions. Here we present results from pulsed field gradient experimentsdesigned to compare the effective hydrodynamic radii of a protein in nativeand non-native states. Measurements performed on lysozyme indicate that theeffective hydrodynamic radius increases by 38±1% on unfolding in urea,a result completely consistent with a recent study by small-angle X-rayscattering.[PUBLICATION ABSTRACT]