title: Effects of Spatially Dependent Mobilities on the Kinetics of the Diffusion-Controlled Association Derived from the First-Passage-Time Approach.
abstract: Brownian dynamics (BD) simulations and the first-passage-time approach are applied to investigate diffusion-controlled association in a biologically relevant model system consisting of a fixed receptor with an elongated cavity and a capsule-like ligand that fits this cavity precisely. Before the binding at the receptor cavity, the ligand undergoes translational and rotational diffusion, either free or under the influence of electrostatic interactions with the receptor. The spatial dependence of the translational and rotational mobilities of the ligand resulting from its hydrodynamic interactions (HIs) with the receptor is accounted for in BD simulations, and an accurate numerical approach is applied for the evaluation of the spatially dependent mobility tensor of the ligand. Different magnitudes of electrostatic interactions (either attraction or repulsion) between the ligand and receptor are considered. The effective range of receptor-ligand electrostatic interactions is varied to account for their screening under different conditions of ionic strength. The effects of HIs on the kinetics of the diffusion-controlled association, evaluated for different electrostatic properties of binding partners, are thoroughly analyzed and discussed.
authors.affiliation: Centre of New Technologies, University of Warsaw , Stefana Banacha 2c, Warsaw 02-097, Poland.
authors.forename: Maciej
authors.initials: M
authors.lastname: Długosz
authors.affiliation: Department of Biophysics, Faculty of Physics, University of Warsaw , Żwirki i Wigury 93, Warsaw 02-089, Poland.
authors.forename: Jan M
authors.initials: JM
authors.lastname: Antosiewicz