Solution Conformations of Penta and Heptapeptides Containing Repetitive \alpha-Aminoisobutyryl-L-Alanyl and \alpha-Aminoisobutyryl-L-Valyl Sequences

Vijayakumar, EKS and Balaram, P (1983) Solution Conformations of Penta and Heptapeptides Containing Repetitive \alpha-Aminoisobutyryl-L-Alanyl and \alpha-Aminoisobutyryl-L-Valyl Sequences. In: Tetrahedron, 39 (16). pp. 2725-2731.

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Abstract

The presence of folded solution conformations in the peptides $Boc-Ala-{(Aib-Ala)}_2-OMe$, $Boc-Val-{(Aib-Val)}_2-OMe$, $Boc-Ala-{(Aib-Ala)}_3-OMe$ and $Boc-Val-{(Aib-Val)}_3-OMe$ has been established by 270MHz H NMR. Intramolecularly H-bonded NH groups have been identified using temperature and solvent dependence of NH chemical shifts and paramagnetic radical induced broadening of NH resonances. Both pentapeptides adopt $3_{10}$ helical conformations possessing 3 intramolecular H-bonds in $CD{Cl}_3$ and ${({CD}_3)}_2SO$. The heptapeptides favour helical structures with 5 H-bonds in $CD{Cl}_3$. In ${({CD}_3)}_2SO$ only 4 H-bonds are readily detected.

Item Type:	Journal Article
Publication:	Tetrahedron
Publisher:	Elsevier
Additional Information:	Copyright for this article belongs to Elsevier Science Ltd.
Department/Centre:	Division of Biological Sciences > Molecular Biophysics Unit
Date Deposited:	15 Mar 2005
Last Modified:	19 Sep 2010 04:18
URI:	http://eprints.iisc.ac.in/id/eprint/2905

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