How Negatively Charged Proteins Adsorb to Negatively Charged Surfaces: A Molecular Dynamics Study of BSA Adsorption on Silica.

How proteins adsorb to inorganic material surfaces is critically important for the development of new biotechnologies, since the orientation and structure of the adsorbed proteins impacts their functionality. While it is known that many negatively charged proteins readily adsorb to negatively charged oxide surfaces, a detailed understanding of how this process occurs is lacking. In this work we study the adsorption of BSA, an important transport protein that is negatively charged at physiological conditions, to a model silica surface that is also negatively charged. We use fully atomistic molecular dynamics to provide detailed understanding of the noncovalent interactions that bind the BSA to the silica surface. Our results provide new insight into the competing roles of long-range electrostatics and short-range forces, and the consequences this has for the orientation and structure of the adsorbed proteins.