Related Experiment Videos
Ion channel formation by zervamicin-IIB. A molecular modelling study
M S Sansom1, P Balaram, I L Karle
1Laboratory of Molecular Biophysics, University of Oxford, UK.
European Biophysics Journal : EBJ
|January 1, 1993
Summary
Zervamicin-IIB (Zrv-IIB) forms voltage-gated ion channels in lipid bilayers. Molecular modeling reveals these peptaibol channels are helix bundles, with flexible sidechains facilitating ion and water transport.
Area of Science:
- Biophysics
- Molecular Biology
- Structural Biology
Background:
- Zervamicin-IIB (Zrv-IIB) is a peptaibol known to form voltage-activated channels in lipid bilayers.
- Understanding the molecular basis of Zrv-IIB channel structure and function is crucial for ion transport studies.
Purpose of the Study:
- To present a molecular model of Zrv-IIB channels.
- To investigate the structural basis for ion and water permeation through Zrv-IIB channels.
Main Methods:
- Molecular modeling based on Zervamicin-Leu crystal structure.
- Analysis of interaction energy profiles for K+, Cl-, and water probes.
- Optimization of polar sidechain conformations within the channel model.
Main Results:
- Zrv-IIB channels are modeled as bundles of 4-8 parallel helices with a central pore.
- Hydrogen bonds between Gln11 and Hyp10 stabilize the helix bundles.
- Optimized sidechain conformations of Gln3, Hyp10, and the C-terminus favor probe interactions.
Conclusions:
- The molecular model provides insights into Zrv-IIB channel architecture.
- Conformational flexibility of polar sidechains allows the channel to mimic an aqueous environment.
- This flexibility is key to facilitating the passage of ions (K+, Cl-) and water.