Cystine peptides: the intramolecular antiparallel β-sheet conformation of a 20-membered cyclic peptide disulfide

Kishore, R. ; Raghothama, S. ; Balaram, P. (1987) Cystine peptides: the intramolecular antiparallel β-sheet conformation of a 20-membered cyclic peptide disulfide Biopolymers, 26 (6). pp. 873-891. ISSN ISSN

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Official URL: http://www3.interscience.wiley.com/journal/1075886...

Related URL: http://dx.doi.org/10.1002/bip.360260608

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 CDCl3. Evidence for peptide aggregation in CDCl3 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 (CD3)2SO to CDCl3. Hydrogen-bonding studies, together with unusually low field positions of the Cys(1) and Cys(6) CαH resonances and high JHNCαH values provide support for an intramolecular antiparallel β-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′ β -turn at the Aib-Ala residues, the site of the chain reversal.

Item Type:Article
Source:Copyright of this article belongs to John Wiley and Sons, Inc.
ID Code:4321
Deposited On:18 Oct 2010 08:56
Last Modified:16 May 2016 14:59

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