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Cystine Peptides: The Intramolecular Antiparallel \beta Sheet Conformation Of A 20-membered Cyclic Peptide Disulfide
| Content Provider | Indian Institute of Science (IISc) |
|---|---|
| Author | Kishore, R. Raghothama, S. Balaram, P. |
| Copyright Year | 1987 |
| Abstract | A 20-membered cyclic peptide disulfide has been synthesized as a conformational model for disulfide loops of limited ring size. 1H-nmr studies at 270 MHz establish the presence of three intramolecular hydrogen bonds involving the Leu, Val, and methylamide NH groups in $CDCl_3$. Evidence for peptide aggregation in $CDCl_3$ is also presented. A structural transition involving loosening of the hydrogen bond formed by the Val NH group is observed upon the measured addition of $(CD_3)_2SO$ to $CDCl_3$. Hydrogen-bonding studies, together with unusually low field positions of the Cys(1) and Cys(6) C H resonances and high $J_{HNC.H}$ values provide support for an intramolecular antiparallel \beta-sheet conformation, facilitated by a chain reversal at the Aib-Ala segment. Extensive nuclear Overhauser effect studies provide compelling evidence for the proposed conformation and also establish a type I'\beta-turn at the Aib-Ala residues, the site of the chain reversal. |
| File Format | |
| Journal | PeerReviewed |
| Language | English |
| Publisher | John Wiley & Sons Inc |
| Publisher Date | 1987-01-01 |
| Access Restriction | Authorized |
| Subject Keyword | Molecular Biophysics Unit Sophisticated Instruments Facility |
| Content Type | Text |
| Resource Type | Article |
