Studies on cyclic peptides. III. The specific interaction of cyclic peptides with benzene and an application of the solvent-induced nmr shift to the conformational analysis of cyclo-(Pro-Sar-Gly)2
✍ Scribed by Toshiharu Sugihara; Yukio Imanishi; Toshinobu Higashimura
- Publisher
- Wiley (John Wiley & Sons)
- Year
- 1975
- Tongue
- English
- Weight
- 661 KB
- Volume
- 14
- Category
- Article
- ISSN
- 0006-3525
No coin nor oath required. For personal study only.
✦ Synopsis
The interaction between cyclic peptides [cyclo-(Sara), cyclo-(Pro-Sar-Gly)r, cyclo-(Sar-Sar), and cyclo-(Sar-Gly)] with benzene has been investigated by nmr spectroscopy. The experiment with cyclo-(Sarr) showed that benzene int,eracted preferentially with the frans peptide bond in a similar manner to the dimethylformaniidebenzene interaction. The solvent-induced nmr shift was then applied to the conformational analysis of cyclo-(Pro-Sar-Gly)? with the aid of the'molecular model. The major conformation was proved to possess the C? symmetry with internally hydrogenbonded glycine residues, in which all peptide bonds were trans. The interaction of cyclo-(Sar-Sar) and cyclo-(Sar-Gly) with benzene was also studied. The association constant was 0.115-kg solut.ion per mole of cyclo-(Sar-Sar) and 0.089-kg solution per mole of cyclo-(Sar-Gly ) in chloroform.