Computational Study of PCSK9-EGFA Complex with Effective Polarizable Bond Force Field

Area of Science:

• Biochemistry
• Computational Biology
• Pharmacology

Background:

• Inhibiting Proprotein Convertase Subtilisin/Kexin-type 9 (PCSK9) binding to the Low Density Lipoprotein Receptor (LDLR) effectively lowers LDL-cholesterol (LDL-C).
• Understanding the PCSK9-LDLR interaction is vital for developing novel PCSK9 inhibitors.
• Gain-of-function mutants of PCSK9 were studied to probe interaction dynamics.

Purpose of the Study:

• To evaluate the reliability of standard AMBER and effective polarizable bond (EPB) force fields in simulating PCSK9-LDLR interactions.
• To assess the impact of polarization effects on molecular dynamics (MD) simulations of protein-protein interactions.
• To guide the design of more accurate computational models for drug discovery.

Main Methods:

• Performed MD simulations using standard AMBER and EPB force fields for wild-type and mutant PCSK9-EGFA domain complexes.
• Analyzed hydrogen bond dynamics to assess simulation stability and structural integrity.
• Calculated relative binding free energies to compare the accuracy of the force fields.

Main Results:

• Standard AMBER force field simulations produced structures deviating significantly from crystal structures, losing key interactions.
• EPB force field simulations yielded more stable structures and relative binding free energies consistent with experimental data.
• Hydrogen bond analysis indicated superior reliability of the EPB force field for protein dynamics.

Conclusions:

• Polarization effects are critical for accurate MD simulations of protein-protein interactions, particularly for PCSK9-LDLR binding.
• The EPB force field offers a more reliable approach for simulating PCSK9-LDLR interactions compared to standard AMBER.
• Accurate simulations using EPB can enhance the design and development of effective PCSK9 inhibitors for managing hypercholesterolemia.