How hydrophobic drying forces impact the kinetics of molecular recognition

Abstract

A model of protein-ligand binding kinetics in which slow solvent dynamics results from hydrophobic drying transitions is investigated. Molecular dynamics simulations show that solvent in the receptor pocket can fluctuate between wet and dry states with lifetimes in each state that are long enough for the extraction of a separable potential of mean force and wet-to-dry transitions. We introduce a Diffusive Surface Hopping Model that is represented by a two-dimensional Markovian master equation. One dimension is the standard reaction coordinate, the ligand-pocket separation, and the other is the solvent state in the region between ligand and binding pocket which specifies whether it is wet or dry. In our model, the ligand diffuses on a dynamic free energy surface which undergoes kinetic transitions between the wet and dry states. The model yields good agreement with results from explicit solvent molecular dynamics simulation and an improved description of the kinetics of hydrophobic assembly. Furthermore, it is consistent with a "non-Markovian Brownian theory" for the ligand-pocket separation coordinate alone.

17 pages, 10 Figures

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Cited by in corpus (9)

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• Variational implicit-solvent predictions of the dry-wet transition pathways for ligand-receptor binding and unbinding kinetics
• On the Role of Solvent in Hydrophobic Cavity-ligand Recognition Kinetics
• Affinity, Kinetics, and Pathways of Anisotropic Ligands Binding to Hydrophobic Model Pockets
• Resonance Reaction in Diffusion-Influenced Bimolecular Reactions