STUDIES ON 2D-NMR OF THE SOLUTION CONFORM ATION OF A DODECACYCLOPEPTIDE

A dodecacyclopeptide, which was used as a supporting template in templ ate assembled synthetic approach for four-helix-bundle proteins, was s tudied by solution 2D-NMR and distance geometry calculations. All hydr ogen atoms in the molecule were assigned by analysis of its 2D-COSY an d NOESY spectra. DIANA distance geometry calculations were carried out with 62 interatomic distances derived from NOE cross peak intensities . Among the 100 structures obtained, the top 10 structures with lowest target function values were selected as final results. The main chain atom r. m. s. between this 10 structures was 0.029 +/- 0.006nm, showi ng very rigid conformation of the dodecacyclopeptide molecule. The fou r lysine side chains used as attaching points for four helix were foun d facing towards the same side of the cyclopeptide ring, showing the v alidity of utilizing this dodecacyclopeptide in the synthesis of four- helix-bundle proteins.