Berlin 2015 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 17: Posters: Protein structure and dynamics
BP 17.17: Poster
Montag, 16. März 2015, 17:30–19:30, Poster A
Selective Adsorption of Similar-Sized Proteins into a Nanoporous Silica Glass — •Sebastian T Moerz1,2 and Patrick Huber1,2 — 1Experimental Physics, Saarland University, D-66041 Saarbruecken — 2Institute of Materials Physics and Technology, Hamburg University of Technology, D-21073 Hamburg
The adsorption of lysozyme, cytochrome c and myoglobin, similar-sized globular proteins of approximately 1.5 nm radius, into the mesoporous silica material SBA-15 with 3.3 nm mean pore radius has been studied photometrically for aqueous solutions containing a single protein type and for binary protein mixtures. Distinct variations in the absolute and relative adsorption behaviour are observed as a function of the solution's pH-value, and thus pore wall and protein charge. The proteins exhibit the strongest binding below their isoelectric points, which indicates the dominance of electrostatic interactions between charged amino acid residues and the -OH groups of the silica surface in the nanopore adsorption process. Moreover, we find for competitive adsorption in the restricted, tubular nano pore geometry that the protein type which shows the favoured binding to the pore wall can entirely suppress the adsorption of the species with lower binding affinity, even though the latter would adsorb quite well from a single component mixture devoid of the strongly binding protein. We demonstrate that this different electrochemical behaviour along with the large specific surface and thus adsorption capability of the nanoporous glass can be readily exploited for a simple, yet highly effective separation of protein mixtures by adjusting the aqueous solution's pH.