Polyelectrolyte Nature of Cytoskeleton Filaments and Their Properties

A variety of dynamic functions of cytoskeletal filaments, such as cellular transport, motility, etc, involve interactions with other proteins and filaments, which are often dominated by electrostatic interactions, and many times mediated and modulated by the biological environment. Little is known about how these electrostatic property differences may affect our molecular understanding in not only the function, and behavior of F-actin, but also the electrostatics governing the interaction with other proteins and membranes. We describe our preliminary theoretical and experimental findings on the biological environment effects on the electrostatic properties under a variety of electrolyte solution conditions. We implemented a full atomistic description of the molecular structure of F-actin to study the surface electric potential and the iso-surface charge density distribution. We also used a molecular solvation electrical double layer theory, developed by our group (J. Chem. Phys. 141,225103, 2014), to study the corresponding hydration and layering formation effects. We found a strong correlation between pH, electrolyte concentration, and water crowding effects, which were observed to highly impact the formation and properties of the electrical double layer around the filaments.