Association equilibria for proteins interacted with crowders of short-range attraction in crowded environment

Abstract

Based on a very simple coarse-grained colloidal model, here we implement an effective hard-sphere theory and numerical simulation to capture the general features of the association equilibria for globular proteins in crowded environment. We measure the activity coefficient, i.e., the deviation from ideal behavior of protein solution, and the crowding factor, i.e., the contribution of crowders to the association equilibria, for proteins in macromolecular crowding. The results show that the association balance in macromolecular crowding depends sensitively on the magnitude of protein–crowder attraction and the relative size of reactant to crowding agent. Since our coarse-grained model is irrelevant to the microscopic details of the molecules, it can be applied to the control of the association equilibria of many globular proteins such as bovine serum albumin, crystallin and lysozyme.