Valle, G and Crisma, M and Toniolo, C and Sudhanand, * and Sukumar, M and Balaram, P and Rao, R Balaji (1991) Stereochemistry of peptides containing 1-aminocycloheptane-1-carboxylic acid (Ac7c). In: International Journal of Peptide & Protein Research, 38 (6). pp. 511-518.Full text not available from this repository. (Request a copy)
The crystal structures of four peptides incorporating 1-aminocycloheptane-1-carboxylic acid (Ac7c) are described. Boc-Aib-Ac7c-NHMe and Boc-Pro-Ac7c-Ala-OMe adopt beta-turn conformations stabilized by an intramolecular 4----1 hydrogen bond, the former folding into a type-I/III beta-turn and the latter into a type-II beta-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 beta-turn conformations in solution.
|Item Type:||Journal Article|
|Additional Information:||Copy right of this article belongs toNational Center for Biotechnology Information.|
|Department/Centre:||Division of Biological Sciences > Molecular Biophysics Unit|
|Date Deposited:||20 May 2010 05:10|
|Last Modified:||20 May 2010 05:10|
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