An Unusual C–H . . . O Hydrogen Bond Mediated Reversal of Polypeptide Chain Direction in a Synthetic Peptide Helix

Aravinda, S and Shamala, N and Pramanik, Animesh and Das, Chittaranjan and Balaram, P (2000) An Unusual C–H . . . O Hydrogen Bond Mediated Reversal of Polypeptide Chain Direction in a Synthetic Peptide Helix. In: Biochemical and Biophysical Research Communications, 273 (3). pp. 933-936.

PDF mediated.pdf Restricted to Registered users only Download (66kB) | Request a copy

Abstract

An unusual C-terminal conformation has been detected in a synthetic decapeptide designed to analyze the stereochemistry of helix termination in polypeptides. The crystal structure of the decapeptide Boc-Leu-Aib-Val-Ala-Leu-Aib-Val-DAla-DLeu-Aib-OMe reveals a helical segment spanning residues 1–7 and helix termination by formation of a Schellman motif, generated by DAla(8) adopting the left-handed helical (aL) conformation. The extended conformation at DLeu(9) results in a compact folded structure, stabilized by a potentially strong C-H . . . O hydrogen bond between Ala(4) CaH and DLeu(9) CO. The parameters for C-H . . . O interaction are Ala(4) CaH. . O=C DLeu(9) distance 3.27 Å, Ca-H . . O angle 176°, and O . . Ha distance 2.29 Å. This structure suggests that insertion of contiguous D-residues may provide a handle for the generation of designed structures containing more than one helical segment folded in a compact manner.

Item Type:	Journal Article
Publication:	Biochemical and Biophysical Research Communications
Publisher:	Academic Press
Additional Information:	Copyright for this article belongs to Academic Press
Keywords:	C-H . . . O hydrogen bond;Conformational analysis;Helix termination;Peptide design;Schellman motif;X-ray structure
Department/Centre:	Division of Biological Sciences > Molecular Biophysics Unit Division of Physical & Mathematical Sciences > Physics
Date Deposited:	26 Aug 2004
Last Modified:	19 Sep 2010 04:14
URI:	http://eprints.iisc.ac.in/id/eprint/1348

Actions (login required)

View Item