Influence of Charge Regulation and Charge Heterogeneity on Complexation between Weak Polyelectrolytes and Weak Proteins Near Isoelectric Point

Abstract

AbstractA combination of constant pH method and single chain in mean field simulations is employed to probe the influence of charge regulation and charge heterogeneities on the bridging characteristics of dissociable polyelectrolytes on globular proteins. By adopting a coarse‐grained representation of proteins as spherical particles, the influence of charge patches on the polyelectrolyte bridging probabilities near protein isoelectric points and in regimes in which the net charge of the protein is the same sign as that of the polyelectrolytes is probed. The results demonstrate that in the presence of dissociable polyelectrolytes, the probability of bridging of proteins capable of charge regulation is higher relative to proteins which are completely dissociated. For homogeneously charged proteins and/or proteins with weak charge heterogeneities, partially dissociated polyelectrolytes are seen to exhibit enhanced bridging characteristics compared to completely dissociated polyelectrolytes. In contrast, for proteins exhibiting strong charge heterogeneities, dissociable polyelectrolytes are seen to exhibit weaker bridging compared to completely dissociated polyelectrolytes.