Dresden 2011 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 38: Poster: Colloids and Complex Liquids
CPP 38.1: Poster
Wednesday, March 16, 2011, 17:00–19:00, P2
Hydration and Protein Interactions in Concentrated Electrolyte Solutions Studied by SANS — •Fajun Zhang1, Maximilian W. A. Skoda2, Robert M. J. Jacobs3, Philip Callow4, Henrich Frielinghaus5, Vitaliy Pipich5, Sylvain Prevost6, and Frank Schreiber1 — 1Institut für Angewandte Physik, Universität Tübingen, Germany — 2ISIS, Rutherford Appleton Laboratory, UK — 3CRL, University of Oxford, UK — 4Institut Laue Langevin, Grenoble, France — 5Jülich Centre for Neutron Science at FRM II, Garching, Germany — 6Helmholtz Center Berlin, Germany
Proteins are commonly found in relatively concentrated salt solutions during protein crystallization and purification. The exact interplay of the hydration shell, the salt ions, and protein-protein interactions under these conditions are far from understood on a fundamental level, despite the obvious practical relevance. We have studied a model globular protein (bovine serum albumin, BSA) in concentrated salt solutions by SANS. By comparing with previous studies using SAXS [1], a hydration level of 0.37 g/g protein is determined. The forward intensity determined from Guinier analysis is used to determine the second virial coefficient, A2, which describes the overall protein interactions in solution. It is found that A2 follows the reverse order of the Hofmeister series. These effects are further discussed by comparing the contribution from the excluded volume. SANS data are further analyzed on the full q-range using liquid theoretical approaches, which is consistent with A2 and the experimental structure factor. [1] F. Zhang, et al., J. Phys. Chem. B 2007, 111, 251.