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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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|
|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|
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