Replica Exchange with Hybrid Tempering Efficiently Samples PGLa Peptide Binding to Anionic Bilayer.

Area of Science:

• Biomolecular simulations
• Computational biophysics
• Membrane biophysics

Background:

• Antimicrobial peptides (AMPs) are crucial in innate immunity.
• Understanding peptide-lipid interactions is key to AMP function.
• All-atom explicit water simulations are vital for accurate biomolecular modeling.

Purpose of the Study:

• To evaluate replica exchange with hybrid tempering (REHT) for biomolecular simulations.
• To compare REHT with replica exchange with solute tempering (REST) for peptide-lipid interactions.
• To elucidate the binding mechanism of antimicrobial peptide PGLa to a lipid bilayer.

Main Methods:

• All-atom explicit water molecular dynamics simulations.
• Replica exchange with hybrid tempering (REHT) algorithm.
• Replica exchange with solute tempering (REST) algorithm.
• Free energy landscape analysis.

Main Results:

• REHT accurately captures PGLa's helical structure and binding mechanism.
• Two main binding states identified: surface-bound and inserted.
• PGLa binding alters lipid bilayer structure and dynamics.
• REHT demonstrates faster equilibration and better accuracy than REST for PGLa binding.

Conclusions:

• REHT is a more efficient and accurate method for studying interfacial biomolecular systems like peptide-lipid interactions.
• Electrostatic interactions are the primary driving force for PGLa binding.
• REHT provides superior peptide equilibration and detailed binding insights compared to REST.