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BP: Fachverband Biologische Physik
BP 32: Posters: Other Topics in Biological Physics
BP 32.3: Poster
Thursday, March 17, 2011, 17:15–20:00, P3
The effect of glycerol and DMSO on the phase behavior of lysozyme — •Christoph Gögelein1, Gerhard Nägele2, Dana Wagner3, Frederic Cardinaux3, and Stefan U. Egelhaaf3 — 1Max-Planck-Institut für Dynamik und Selbstorganisation, Bunsenstr. 10, 37073 Göttingen — 2Forschungszentrum Jülich, 52425 Jülich — 3Heinrich-Heine-Universität Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf
Additives such as salt, glycerol and dimethyl sulfoxide (DMSO) are widely used to modify the stability of protein solutions [1]. In this work, we study the effect of these additives on the second virial coefficient and the phase behavior of lysozyme. We show that glycerol reduces the attractive interaction of lysozyme, whereas the addition of sodium chloride increases the attraction by screening the protein electrostatic charges. Adding DMSO amplifies the strength of the interaction potential so that the influence of the temperature on the second virial coefficient becomes more pronounced. We compare our experimental findings with theoretical predictions based on the Derjaguin-Landau-Verwey-Overbeek (DLVO) effective pair potential for the protein interaction. Moreover, we compute the crystallization and gas-liquid coexistence curves using thermodynamic perturbation theory (TPT). It is shown that the DLVO-type description predicts qualitatively the influence of salt and glycerol. However, the DLVO model fails to describe the effect of DMSO.
[1] H. Sedgwick, J. E. Cameron, W. C. K. Poon, and S. U. Egelhaaf, J. Chem. Phys. 127 (2007), 125102.