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Conformational Flexibility in Enkephalins: Solvent Dependent Transitions in Peptides with Gly-Gly Segments Detected by Circular Dichroism

Sudha, TS and Balaram, P (1981) Conformational Flexibility in Enkephalins: Solvent Dependent Transitions in Peptides with Gly-Gly Segments Detected by Circular Dichroism. In: FEBS Letters, 134 (1). pp. 32-36.

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Abstract

The widespread interest in developing structure-activity correlations for opioid peptides [1-3] has led to a large number of investigations on the preferred solution conformations of enkephalins [4-11]. The results of these studies have led to proposals ranging from \beta-turn conformations. With ${Gly}^2-{Gly}^3$ [14] or ${Gly}^3-{Phe}^4$ [4-10] as the corner residues. Evidence for the lack of preferred conformations in solutions, resulting from dynamic averaging between an ensemble of structures, has also been presented [11]. While a consensus has yet to be reached on the solution conformations of enkephalins, there is general agreement that receptor interactions presumably involve a folded, defined conformation of the penta-peptide [12-14]. The recognition of multiple receptor sites for opioid ligands [15-17], has provided a further impetus for studies of conformational flexibility in enkephalins, with the possibility that interaction at \mu and \delta sites may be mediated through different conformations of the peptides [18]. Here, we describe an unusual solvent-dependent conformational transition, in the protected fragment $Boc-Gly-Gly-Phe-Met.{NH}_2$ and ${Met}_5$-enkephalinamide which is abolished on restricting conformational freedom by substitution of Gly by \alpha-aminoisobutyryl (Aib) residues [19,20].

Item Type: Journal Article
Additional Information: Copyright for this article belongs to Elsevier Science Ltd.
Department/Centre: Division of Biological Sciences > Molecular Biophysics Unit
Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Date Deposited: 29 Mar 2005
Last Modified: 19 Sep 2010 04:18
URI: http://eprints.iisc.ernet.in/id/eprint/2971

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