The properties of ion channels formed by zervamicins

Balaram, P and Krishna, K and Sukumar, M and Mellor, IR and Sansom, Mark SP (1992) The properties of ion channels formed by zervamicins. In: European Biophysics Journal, 21 (2). pp. 117-128.

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Abstract

The zervamicins (Zrv) are a family of 16 residue peptaibol channel formers, related to the 20 residue peptaibol alamethicin (Alm), but containing a higher proportion of polar sidechains. Zrv-IIB forms multi-level channels in planar lipid (diphytanoyl phosphatidyl- choline) bilayers in response to cis positive voltages. Analysis of the voltage and concentration dependence of macroscopic conductances induced by Zrv-IIB suggests that, on average, channels contain ca. 13 peptide monomers. Analysis of single channel conductance levels suggests a similar value. The pattern of successive conductance levels is consistent with a modified helix bundle model in which the higher order bundle are distorted within the plane of the bilayer towards a "torpedo" shaped cross-section, The kinetics of intra-burst switching between adjacent conductance levels are shown to be approximately an order of magnitude faster for Zrv-IIB than for Ahn. The channel forming properties of the related naturally occurring peptaibols, Zrv-Leu and Zrv-IC, have also been demonstrated, as have those of the synthetic apolar analogue Zrv-Al-16. The experimental studies on channel formation are combined with the known crystallographic structures of Zrv-Al-16 and Zrv- Leu to develop a molecular model of Zrv-IIB channels.

Item Type:	Journal Article
Publication:	European Biophysics Journal
Publisher:	Springer
Additional Information:	Copyright of this article belongs to Springer.
Keywords:	Ion channel;Peptaibol;Channel forming Peptide;Planar bilayer
Department/Centre:	Division of Biological Sciences > Molecular Biophysics Unit
Date Deposited:	13 Oct 2006
Last Modified:	19 Sep 2010 04:32
URI:	http://eprints.iisc.ac.in/id/eprint/8860

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