STUDIES ON THE beta -TURN OF PEPTIDES. V. TURN PREFERENCE OF PEPTIDE SEQUENCES ANALYZED BY CONFORMATIONAL ENERGY CALCULATION ON DIPEPTIDE MODELS AND BY CD SPECTRA OF CHROMOPHORIC DERIVATIVES.

Article abstract of DOI:10.1246/bcsj.56.3005

Empirical conformational energy calculations were performed on Ac-L-Pro-D-Ala-NHCH//3 and AC-D-Ala-L-Pro-NHCH//3. In order to study the turn tendency of the dipeptide sequences turn probabilities and average interterminal distances were calculated. Much larger turn preference of D-Ala containing sequences was indicated compared with the corresponding L-Ala containing sequences. The turn tendency of the dipeptide sequences were shown to be in the order: L-Pro-D-Ala greater than D-Ala-L-Pro greater than L-ProL-Ala greater than L-Ala-L-Pro. This order coincides with the order of the magnitude of the Cotton effects in the CD spectra of the chromophoric derivatives having 2,4-dinitrophenylglycyl and glycine-p-nitroanilide at the N- and the C-termini, respectively, of the corresponding dipeptide sequences using chromophoric derivatives reported earlier.