NISCAIR Online Periodicals Repository

Research Journals >
Indian Journal of Biochemistry and Biophysics (IJBB) >
IJBB Vol.40 [2003] >
IJBB Vol.40(4) [August 2003] >

Title: Effect of terminal achiral and chiral residues on the conformational behaviour of poly ΔZPhe and analysis of various interactions
Authors: Nandel, Fateh S
Kaur, Harpreet
Keywords: poly-dehydrophenylalanine
chiral amino acid
residue effect
design of peptide
Issue Date: Aug-2003
Publisher: CSIR
Abstract: Conformational properties of the peptides containing (ΔZPhe)6 with achiral (ΔAla, Gly) and chiral (Ala, Leu) residues at both the N- and C-terminal positions have been studied with a view to design a peptide with desired helical screw sense. In all the peptides, the lowest energy conformational state corresponds to φ = 0º and Ψ = + 90ºor – 90º or both ± 90º. These structures are characterized by rise per residue of 1.94 Å; rotation per residue of 114º and 3.12 residues per turn and are stabilized by: (i) carbonyl-carbonyl interactions with the carbonyl oxygen of ith residue and carbonyl carbon atom of the carbonyl group of ith+1 residue; and (ii) N-H…π interactions between the amino group of ΔZPhe and its own aromatic moiety. The Ala/Leu residues at the N-terminus further stabilized the structure, through C-H…π interactions with the farthest edge of the aromatic ring of ith+3 ΔZPhe residue. For peptides Ac-L-Ala/L-Leu-(ΔZPhe)6-NHMe, the low energy left handed helical structure (~2.5 Kcalmol-1 higher in energy) state corresponds to φ = -30º, Ψ = 120º for L-residue and φ = Ψ = 30º for ΔZPhe residues and is in good agreement with the X-ray crystallography results for the peptide Boc-L-Ala-(ΔZPhe)4-NHMe crystals grown from acetonitrile/ethanol mixture. Computational results suggest that the peptides Ac-D-Ala/D-Leu-(ΔZPhe)6-NHMe adopt a right handed helical structure in polar solvents with φ = 30º, Ψ = -120º for D-residues and φ = Ψ = -30º for ΔZPhe residues. Both in the left handed and right handed structures, the carbonyl oxygen of acetyl group is involved in 10-membered hydrogen bonded ring formation with NH of 3rd ΔZPhe residue whereas ΔZPheresidues backbone adopts a 310 helix structure. Computational results also suggest that the conformational state with φ = 0º and Ψ = 90º can be realized by keeping D-Ala or D-Leu at the C-terminal. There is hardly any effect of achiral residues Gly/ΔAla on the conformational behaviour of poly-ΔZPhe.
Page(s): 265-273
ISSN: 0301-1208
Source:IJBB Vol.40(4) [August 2003]

Files in This Item:

File Description SizeFormat
IJBB 40(4) 265-273.pdf150.91 kBAdobe PDFView/Open
 Current Page Visits: 87 
Recommend this item


Online Submission of Articles |  NISCAIR Website |  National Knowledge Resources Consortium |  Contact us |  Feedback

Disclaimer: NISCAIR assumes no responsibility for the statements and opinions advanced by contributors. The editorial staff in its work of examining papers received for publication is helped, in an honorary capacity, by many distinguished engineers and scientists.

CC License Except where otherwise noted, the Articles on this site are licensed under Creative Commons License: CC Attribution-Noncommercial-No Derivative Works 2.5 India

Copyright © 2015 The Council of Scientific and Industrial Research, New Delhi. All rights reserved.

Powered by DSpace Copyright © 2002-2007 MIT and Hewlett-Packard | Compliant to OAI-PMH V 2.0

Home Page Total Visits: 169668 since 01-Sep-2015  Last updated on 30-Jun-2016Webmaster: