Design of peptides with α, β-dehydro-residues: synthesis and crystal structure of a tripeptide N-benzyloxycarbonyl-ΔVal-ΔPhe-L-Ala-OCH3

Goel, Vijay Kumar ; Dey, Sharmistha ; Singh, Tej P. (2005) Design of peptides with α, β-dehydro-residues: synthesis and crystal structure of a tripeptide N-benzyloxycarbonyl-ΔVal-ΔPhe-L-Ala-OCH3 Journal of Molecular Structure, 738 (1-3). pp. 189-192. ISSN 0022-2860

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Official URL: http://linkinghub.elsevier.com/retrieve/pii/S00222...

Related URL: http://dx.doi.org/10.1016/j.molstruc.2004.12.005

Abstract

In order to develop the design rules for producing specific conformations of peptides with α, β-dehydro-residues a peptide Cbz-ΔVal-ΔPhe-Ala-OCH3 was synthesized in solution phase. The crystal structure has been determined by X-ray diffraction method. The structure was refined to an R-value of 0.050. The peptide adopts a type I β-turn conformation with backbone torsion angles of two corner residues, Φ1=-53.9(6)°, Ψ1=-33.0(6)°, Φ2=-73.7(5)° and Ψ2=-12.2(6)°. The conformation is stabilized by an intramolecular 4→1 hydrogen bond involving NH of Ala residue as a donor and carbonyl oxygen atom of Cbz group as an acceptor. The torsion angles,x11,1=172.8(6)and x11,2=-6.9(9) of ΔVal residue indicate that its side chain is planar while the torsion angles,x12=-9.0(9) ,x21,2=-43.4(10) and x22,2=130.1(9) show that the side chain of ΔPhe deviates considerably from the planarity. This is the first sequence in which ΔVal and ΔPhe are introduced at adjacent positions and the structure reveals clearly that the side chain of ΔPhe is a relatively less rigid than that of ΔVal. The molecules are packed in columns parallel to c-axis.

Item Type:Article
Source:Copyright of this article belongs to Elsevier Science.
Keywords:α,β-Dehydro-Residue; β-Turn; Hydrogen Bond; Conformation; Crystal Structure
ID Code:49144
Deposited On:19 Jul 2011 04:15
Last Modified:19 Jul 2011 04:15

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