Conformational studies of cyclo(L-Phe-L-Pro-Gly-L-Pro)2 by 13C nuclear magnetic resonance.
The 13C-NMR spectrum (Fig. 2,1) of cyclooctapeptide cyclo(L-phe-L-Pro-Gly-L-Pro)2 (A) in CDC13 suggested that its conformation involved the coexistence of two kinds of C2-symmetric conformation with trans-trans-trans-trans and cis-trans-trans-trans forms. Adding 0.5 equivalent of CsSCN or one equivalent of DL-Phe-OMe.HCl to the solution of cyclopeptide (A) in CDC13 yielded 13C-NMR spectra (Fig. 2,2 and Table I) which suggested a single C2-symmetric conformation with trans-trans-trans-trans form, resulting from the formation of complexes with CsSCN or DL-Phe-OMe.HCl. The 13C-NMR spectrum of complexes of A with DL-Phe-OMe.HCl displayed separate resonances for C(gamma), C(o), C(m), C(alpha), and C(beta) of D-Phe-OMe.HCl and L-Phe-OMe.HCl (Table I).
Faculty of Pharmacy and Pharmaceutical Sciences, Fukuyama University, Hiroshima, Japan.
T
T
Ishizu
A
A
Fujii
S
S
Noguchi
D000595:Amino Acid Sequence; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D010456:Peptides, Cyclic / Q000737:chemistry*; D011487:Protein Conformation
D010456:Peptides, Cyclic; C071490:cyclo(phenylalanyl-prolyl-glycyl-prolyl)2