CHARACTERIZATION OF PROTEIN UNFOLDING BY NMR DIFFUSION MEASUREMENTS

The characterisation of non-native stales of proteins is a key problem in studies of protein folding. Complete characterisation of these sta tes requires a description of both local and global properties, includ ing molecular dimensions. Here we present results from pulsed field gr adient experiments designed to compare the effective hydrodynamic radi i of a protein in native and non-native states. Measurements performed on lysozyme indicate that the effective hydrodynamic radius increases by 38+/-1% on unfolding in urea, a result completely consistent with a recent study by small-angle X-ray scattering.