A H-1-NMR STUDY ON THE INTERACTION OF AMINOXYL PARAMAGNETIC PROBES WITH UNFOLDED PEPTIDES

The use of soluble spin labels to filter out the cross peaks of outer proton nuclei in 2D NMR spectra has been proposed as a general method to obtain structural information for complex molecules. Here the param agnetic effects observed on backbone protons of an unfolded 27 amino a cid peptide are discussed. The lack of any differential intensity chan ge of the NH-Halpha cross-peaks in TOCSY spectra is suggested as an ad ditional general criterion for the identification of unfolded structur es.