Peptide Design: Influence of a Guest Aib-Pro Segment on the Stereochemistry of an Oligo-Val Sequence-Solution Conformations and Crystal Structure of Boc-(Val)2-Aib-Pro-(Val)3-OMe

Karle, Isabella L and Flippen-Anderson, Judith L and Uma, K and Balaram, Hemalatha and Balaram, P (1990) Peptide Design: Influence of a Guest Aib-Pro Segment on the Stereochemistry of an Oligo-Val Sequence-Solution Conformations and Crystal Structure of Boc-(Val)2-Aib-Pro-(Val)3-OMe. In: Biopolymers, 29 (10-11). pp. 1433-1442.

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Abstract

The peptide Boc-Val-Val-Aib-Pro-Val-Val-Val-OMe has been synthesized to investigate the effect of introduction of a strong \beta-turn promoting guest segment into an oligopeptide with a tendency to form extended structures. 'H-nmr studies in solution using analysis of NH group solvent accessibility and nuclear Overhauser effects suggest an appreciable solvent dependence of conformations. In chloroform a 310-helical structure is favored, while in dimethylsulfoxide an Aib-Pro \beta-turn with extended arms on either side is suggested. In the crystal, the backbone forms a somewhat distorted 310-helix despite the presence of a Pro residue in the middle. Among the four possible intrahelical hydrogen bonds three are of the 4\rightarrow1 type and one 5\rightarrow1. Head-to-tail NH . . .O=C hydrogen bonds link the helical molecules into continuous columns. The space group is P212121 with a = 11.320 ( 2 ) , b = 19.889(3), and c = 21.247(3) A.

Item Type:	Journal Article
Publication:	Biopolymers
Publisher:	John Wiley & Sons, Inc
Additional Information:	Copyright for this article belongs to John Wiley & Sons, Inc.
Department/Centre:	Division of Biological Sciences > Molecular Biophysics Unit
Date Deposited:	28 Dec 2004
Last Modified:	19 Sep 2010 04:17
URI:	http://eprints.iisc.ac.in/id/eprint/2523

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