Role of a two-residue spacer in an α,β-didehydrophenylalanine containing hexapeptide: crystal and solution structure of Boc-Val-ΔPhe-Leu-Ala-ΔPhe-Ala-OMe

Chauhan, V. S. ; Padyana, Anil K. ; Ramakumar, S. ; Mathur, Puniti ; Jagannathan, N. R. (2003) Role of a two-residue spacer in an α,β-didehydrophenylalanine containing hexapeptide: crystal and solution structure of Boc-Val-ΔPhe-Leu-Ala-ΔPhe-Ala-OMe Journal of Peptide Science, 9 (1). pp. 54-63. ISSN 1075-2617

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Official URL: http://onlinelibrary.wiley.com/doi/10.1002/psc.432...

Related URL: http://dx.doi.org/10.1002/psc.432

Abstract

The peptide Boc-Val1-ΔPhe2-Leu3-Ala4-ΔPhe5-Ala6-OMe has been examined for the structural consequence of placing a two-residue segment between the ΔPhe residues. The peptide is stabilized by four consecutive β-turns. The overall conformation of the molecule is a right-handed 310-helix, with average (Φ, ψ) values (−67.7°, −22.7°), unwound at the C-terminus. The 1H NMR results also suggest that the peptide maintains its 310-helical structure in solution as observed in the crystal state. The crystal structure is stabilized through head-to-tail hydrogen bonds and a repertoire of aromatic interactions laterally directed between adjacent helices, which are antiparallel to each other. The aromatic ring of ΔPhe5 forms the hub of multicentred interactions, namely as a donor in aromatic C-H...π and aromatic C-H...O-C interactions and as an acceptor in a CH3...π interaction. The present structure uniquely illustrates the unusual capability of a ΔPhe ring to host such concerted interactions and suggests its exploitation in introducing long-range interactions in the folding of supersecondary structures.

Item Type:Article
Source:Copyright of this article belongs to European Peptide Society.
Keywords:310-helix; Aromatic Interactions; Constrained Peptides; Crystal and Solution Structure; De Novo Design; Didehydrophenylalanine
ID Code:8192
Deposited On:26 Oct 2010 12:12
Last Modified:30 May 2011 11:16

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