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Unraveling Entropic Rate Acceleration Induced by Solvent Dynamics in Membrane Enzymes
Published on: January 16, 2016
Structural refinement of membrane proteins by restrained molecular dynamics and solvent accessibility data.
Pornthep Sompornpisut1, Benoît Roux, Eduardo Perozo
1Department of Biochemistry and Molecular Biology and Institute for Biophysical Dynamics, University of Chicago, Chicago, Illinois, USA.
Biophysical Journal
|August 5, 2008
Summary
We developed a new method using electron paramagnetic resonance (EPR) data to refine membrane protein structures with molecular dynamics. This approach accurately refolds distorted protein models, aiding structural biology research.
Area of Science:
- Structural biology
- Biophysics
- Computational chemistry
Background:
- Membrane proteins are crucial but challenging to study structurally.
- Electron paramagnetic resonance (EPR) spectroscopy provides valuable solvent accessibility data.
- Integrating EPR data into structural refinement is complex.
Purpose of the Study:
- To present a novel method for incorporating EPR-derived solvent accessibility data into membrane protein structural refinement.
- To validate the approach using molecular dynamics simulations and experimental data.
Main Methods:
- Utilized "pseudoatom-driven solvent accessibility refinement" employing restrained molecular dynamics simulations.
- Parameterized restraints from oxygen (PiO(2)) and nickel-ethylenediaminediacetic acid (PiNiEdda) collision frequencies.
- Simulations incorporated interactions between spin-label pseudoatoms and virtual solvent particles.
Main Results:
- Successfully refolded distorted conformations of the KcsA potassium channel (2-30 Å RMSD) to within 1-3 Å RMSD of the native structure.
- Demonstrated convergence using up to 58 EPR restraints from spin-label mutants.
- Energy-based ranking and clustering effectively identified correctly folded structures.
Conclusions:
- The "pseudoatom-driven solvent accessibility refinement" method is effective for structural refinement of membrane proteins.
- The approach is computationally efficient and applicable to various membrane protein systems.
- This method is particularly useful for calculating conformational changes from known structures.
