ADSORPTION OF COMPLEX PROTEINS AT INTERFACES

We have previously shown that the adsorption of model proteins at model interfaces can be quantitatively understood via a careful consideration of the proteins' three dimensional structure and its stability. Using computer molecular graphics, dynamic surface tension, fluorescence probes and labels, and solution denaturation data, we can relate the chemical and structural properties of proteins to their interface behavior. We have developed a novel means to present these data and correlations in a simple radial plot (the "Tatra" plot). We are now extending these approaches to complex multi-domain proteins. Albumin consists of three large domains with differences in electrostatic nature, charge-pH characteristics, and denaturability. The interfacial activity of albumin is due, at least in part, to the interfacial activity of its constituent domains. Consideration of the structure and interfacial activity of the various domains permits new and more precise hypotheses to be developed, with which new and better experiments can be designed. Such hypotheses allow one to evaluate and compare adsorption data, including kinetics and isotherms, adsorbed layer thickness, refractive index, multilayer formation, etc. We feel strongly that each different protein is a unique molecular personality, which must be understood and considered if we are to more fully understand and apply the interfacial behavior of complex proteins. Expanded treatments of these topics are available in References 1-4.