BETA-TURN INDUCTION BY C-60-BASED FULLEROPROLINE - SYNTHESIS AND CONFORMATIONAL CHARACTERIZATION OF FPR PRO SMALL PEPTIDES/

We have recently described the preparation of Fpr (C-60-based fullerop roline). In this paper the synthesis and a conformational characteriza tion of heterochiral di-and tripeptides containing this new alpha-amin o acid are reported. A folded structure, induced by the -L-Fpr-D-Ala-s equence in chloroform solution and detected by Fourier transform infra red absorption and H-1 nuclear magnetic resonance, has been compared w ith the known propensity of the cognate -L-Pro-D-Ala-sequence to adopt a beta II-turn conformation, which has also been confirmed in this wo rk. The beta II-turn structure is retained in the crystal state by the Pro-peptides, as shown by the X-ray diffraction structures of Ibu-L-P ro-D-Ala-NHtBu and Z-L-Pro-D-Ala-L-Ala-OtBu. (C) Munksgaard 1997.