Electrostatically assisted macroion association

TL;DR

This study uses Monte Carlo simulations to explore how electrostatic and short-range interactions influence macroion association, revealing effects of counterion valency and concentration on dimerization.

Contribution

It introduces a model combining electrostatic and short-range attractions, validated by simulations, to analyze macroion association dynamics.

Findings

Divalent counterions promote macroion dimerization.

Dimerization depends on macroion concentration and binding energy.

Good agreement between Monte Carlo data and theoretical models.

Abstract

A model system of highly asymmetric polyelectrolyte with directional short-range attractive interactions was studied by canonical Monte Carlo computer simulations. Comparison of MC data with previously published theoretical results shows good agreement. For moderate values of binding energies, which matches those of molecular docking, a dynamic equilibrium between free and dimerized macroions is observed. Fraction of dimerized macroions depends on macroion concentration, binding energy magnitude, and on the valency of small counterions. Divalent counterions induce an effective attraction between macroions and enhance dimerization. This effect is most notable at low to moderate macroion concentrations.