Ion channel formation by zervamicin-IIB. A molecular modelling study.

Sansom, MS and Balaram, P and Karle, IL (1993) Ion channel formation by zervamicin-IIB. A molecular modelling study. In: European Biophysics Journal, 21 (6). 369 -383.

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Abstract

Zervamicin-IIB (Zrv-IIB) is a 16 residue peptaibol which forms voltage-activated, multiple conductance level channels in planar lipid bilayers. A molecular model of Zrv-IIB channels is presented. The structure of monomeric Zrv-IIB is based upon the crystal structure of Zervamicin-Leu. The helical backbone is kinked by a hydroxyproline residue at position 10. Zrv-IIB channels are modelled as helix bundles of from 4 to 8 parallel helices surrounding a central pore. The monomers are packed with their C-terminal helical segments in close contact, and the bundles are stabilized by hydrogen bonds between glutamine 11 and hydroxyproline 10 of adjacent helices. Interaction energy profiles for movement of three different probes species (K+, Cl- and water) through the central pore are analyzed. The conformations of: (a) the sidechain of glutamine 3; (b) the hydroxyl group of hydroxyproline 10; and (c) the C-terminal hydroxyl group are "optimized" in order to maximize favourable interactions between the channel and the probes, resulting in favourable interaction energy profiles for all three. This suggests that conformational flexibility of polar sidechains enables the channel lining to mimic an aqueous environment.

Item Type:	Journal Article
Publication:	European Biophysics Journal
Publisher:	Springer
Additional Information:	Copyright of this article belongs to Springer.
Keywords:	Ion channel - Peptaibol - Molecular modelling - Channel-forming peptide.
Department/Centre:	Division of Biological Sciences > Molecular Biophysics Unit
Date Deposited:	19 May 2010 06:57
Last Modified:	19 Sep 2010 06:00
URI:	http://eprints.iisc.ac.in/id/eprint/27294

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