Protein-ligand interactions measured by N-15-filtered diffusion experiments

NMR diffusion coefficient measurements have been shown to be sensitive to t he conformational and oligomeric states of proteins. Recently, heteronuclea r-filtered diffusion experiments have been proposed [Dingley et al. (1997) J. Biomol. NMR, 10, 1-8]. Several new heteronuclear-filtered diffusion puls e sequences are proposed which are shown to have superior sensitivity to th ose previously proposed. One of these new heteronuclear-filtered diffusion experiments has been used to study the binding of an SH3 domain to a peptid e. Using this system, we show that it is possible to measure binding consta nts from diffusion coefficient measurements.