Electrostatic Interactions In and Between Biomolecules

Abstract: Electrostatic interactions in bio-molecular systems are important not only in the living cell but also in more technical applications. Using molecular simulation as well as approximate theories the properties of a number of aqueous protein solutions have been studied. This includes interactions with other proteins, protons, charged membranes as well as flexible polyelectrolytes. The focus is on electrostatic interactions and special attention is put on charge regulation. I.e. how the protonation state of a biomolecule is influenced by nearby charged species. We show that this gives an important contribution to the free energy and that the mechanism can be accounted for by a simple statistical mechanical model. In particular we introduce the concept of protein capacitance that is the key intrinsic property for quantifying the charge regulation.