A 2D NMR study of the internal flexibility of the antifungal peptide stendomycin.

A 2-D 1H NMR study (NOESY, COSY, HOHAHA and ROESY experiments) of the antifungal peptide stendomycin is presented. The variation of the NOESY cross peak intensities is measured as a function of temperature in order to discriminate between constant and fluctuating interproton distances. It is shown that among 71 NOESY cross peaks, only 12 correspond to well defined interproton distances and their correlation time is determined. The other cross peaks cannot be translated accurately in terms of distances owing to internal molecular motions. (1H)-13C nOe measurements confirm the internal mobility of the molecule. Finally a flexibility map of stendomycin can be established.