Electrophysiological Properties from Computations at a Single Voltage: Testing Theory with Stochastic Simulations

Area of Science:

• Computational Biology
• Biophysics
• Molecular Dynamics

Background:

• Calculating ion channel free energy profiles and electrophysiological properties is computationally intensive.
• Existing methods often require multiple simulations at different voltages or knowledge of ion diffusivity.

Purpose of the Study:

• To investigate novel methods for calculating ion channel free energy profiles and electrophysiological properties from single molecular dynamics simulations.
• To reduce the computational burden of probing ion channel behavior.

Main Methods:

• Utilized stochastic simulations to analyze molecular dynamics trajectories.
• Applied two recently developed methods for free energy profile calculation.
• Generated stochastic trajectories mimicking ion channel crossing statistics for trichotoxin, p7, and GLIC models.

Main Results:

• Free energy profiles obtained from modest-length simulations had low statistical errors (0.3 kcal/mol).
• Two-sided formulas significantly reduced statistical errors compared to one-sided formulas.
• Current-voltage curves were accurately reproduced from single-voltage simulations.

Conclusions:

• The developed methods efficiently and accurately determine ion channel electrophysiological properties from single molecular dynamics simulations.
• These approaches offer a computationally advantageous alternative for studying ion channel function.
• Careful selection of reference voltage is crucial for accurate current-voltage curve reconstruction.