Relative Affinities of Protein-Cholesterol Interactions from Equilibrium Molecular Dynamics Simulations

Area of Science:

• Biophysics
• Structural Biology
• Computational Chemistry

Background:

• Lipid-protein interactions are crucial for membrane protein stability and function.
• Molecular dynamics (MD) simulations and cryo-electron microscopy (cryo-EM) increasingly reveal these interactions.
• Quantifying lipid binding affinities is essential for understanding these specific interaction sites.

Purpose of the Study:

• To develop a novel, high-throughput method for determining protein-lipid binding affinities.
• To validate the method by comparing results with existing computational approaches.
• To provide a robust alternative for analyzing lipid interactions in membrane protein structures.

Main Methods:

• Utilized equilibrium coarse-grained MD simulations.
• Employed binding saturation curves, mimicking experimental protocols.
• Applied the method to quantify cholesterol binding affinities to various membrane proteins.

Main Results:

• Successfully obtained protein-lipid binding affinities using the new method.
• Demonstrated good agreement in the ranking of affinities compared to density-based equilibrium methods and potential of mean force calculations.
• Validated the binding saturation method as a robust approach for analyzing lipid-protein interactions.

Conclusions:

• The developed binding saturation method offers a reliable and efficient way to determine relative lipid binding affinities.
• This method can be used to assess the importance of individual lipid interaction sites observed in cryo-EM structures.
• Provides a valuable tool for high-throughput analysis of membrane protein-lipid interactions.