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Automated Lipid Bilayer Membrane Formation Using a Polydimethylsiloxane Thin Film
Published on: July 10, 2016
Alamethicin helices in a bilayer and in solution: molecular dynamics simulations
D P Tieleman1, M S Sansom, H J Berendsen
1BIOSON Research Institute and Department of Biophysical Chemistry, University of Groningen, 9747 AG Groningen, The Netherlands.
Biophysical Journal
|January 6, 1999
Summary
Alamethicin maintains its helical structure in lipid bilayers and methanol, unlike in water. Polar C-terminal interactions anchor the peptide, explaining its asymmetric insertion into membranes.
Area of Science:
- Biophysics
- Computational Biology
- Membrane Protein Dynamics
Background:
- Alamethicin is a voltage-dependent, channel-forming peptide.
- Its insertion into lipid bilayers is asymmetrical.
- Understanding peptide conformation in different environments is crucial.
Purpose of the Study:
- To compare alamethicin conformation and dynamics in water, methanol, and a lipid bilayer.
- To elucidate the molecular basis for alamethicin's asymmetric membrane insertion.
Main Methods:
- Nanosecond molecular dynamics simulations.
- Analysis of peptide conformation (Calpha RMSD).
- Hydrogen-bond interaction analysis.
Main Results:
- Alamethicin retained alpha-helical structure in the bilayer and methanol.
- Significant structural changes, particularly in the C-terminus, occurred in water.
- Hinge-bending motion observed around the Gly-X-X-Pro motif in the bilayer and methanol.
- Polar C-terminal side chains formed persistent H-bonds at the bilayer interface.
Conclusions:
- Alamethicin's helical stability is environment-dependent.
- Polar C-terminal interactions act as an anchor, driving N-terminal insertion.
- This anchoring mechanism explains the voltage-dependent, asymmetric channel activation.
