Stereochemistry of peptides containing 1‐aminocycloheptane‐1‐carboxylic acid (Ac7c)
- 1 December 1991
- journal article
- Published by Wiley in International Journal of Peptide and Protein Research
- Vol. 38 (6) , 511-518
- https://doi.org/10.1111/j.1399-3011.1991.tb01534.x
Abstract
The crystal structures of four peptides incorporating l‐aminocycloheptane‐l‐carboxylic acid (Ac7c) are described. Boc‐Aib‐Ac7c‐NHMe and Boc‐Pro‐Ac7c‐Ala‐OMe adopt β‐turn conformations stabilized by an intramolecular 4 × 1 hydrogen bond, the former folding into a type‐I/III β‐turn and the latter into a type‐II β‐turn. In the dipeptide esters, Boc‐Aib‐Ac7c‐OMe and Boc‐Pro‐Ac7c‐OMe, the Ac7c and Aib residues adopt helical conformations, while the Pro residue remains semi‐extended in both the molecules of Boc‐Pro‐Ac7c‐OMe found in the asymmetric unit. The cycloheptane ring of Ac7c residues adopts a twist‐chair conformation in all the peptides studied. 1H‐NMR studies in CDCl3 and (CD3)2SO and IR studies in CDCl3, suggest that Boc‐Aib‐Ac7c‐NHMe and Boc‐Pro‐Ac7c‐Ala‐OMe maintain the β‐turn conformations in solution.Keywords
This publication has 58 references indexed in Scilit:
- Structural versatility of peptides from Cα,α‐dialkylated glycines. I. A conformational energy computation and x‐ray diffraction study of homo‐peptides from Cα,α‐diethylglycineBiopolymers, 1988
- Geometry of proline and hydroxyproline I: An analysis of X-ray crystal structure dataBiochemical and Biophysical Research Communications, 1986
- A highly active chemotactic peptide analog incorporating the unusual residue 1-aminocyclohexanecarboxylic acid at position 2Biochemical and Biophysical Research Communications, 1985
- Conformations of prolineJournal of the American Chemical Society, 1977
- STUDIES ON THE CONFORMATION OF AMINO ACIDSInternational Journal of Protein Research, 1971
- Studies in molecular structure, symmetry and conformation IIJournal of Chemical Crystallography, 1971
- Conformational analysis. LX. Improved calculations of the structures and energies of hydrocarbons by the Westheimer methodJournal of the American Chemical Society, 1968
- Molecular geometry. V. Evaluation of functions and conformations of medium ringsJournal of the American Chemical Society, 1967
- Molecular Geometry. I. Machine Computation of the Common RingsJournal of the American Chemical Society, 1961
- Identification of Carbonyl Compounds through Conversion into Hydantoins1Journal of the American Chemical Society, 1942