Berlin 2012 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 15: Proteins II
BP 15.7: Vortrag
Mittwoch, 28. März 2012, 16:45–17:00, H 1058
Dynamics of highly concentrated protein solutions around the denaturing transition — •Tilo Seydel1, Marcus Hennig1,2, Felix Roosen-Runge2, Fajun Zhang2, Stefan Zorn2, Maximilian W.A. Skoda3, Robert M.J. Jacobs4, and Frank Schreiber2 — 1Institut Laue-Langevin, Grenoble, France — 2Institut für Angewandte Physik, Universität Tübingen, Germany — 3ISIS, RAL, Chilton, Didcot, UK — 4CRL, University of Oxford, UK
We discuss the dynamics of highly concentrated aqueous protein solutions around the denaturing transition [1]. For the temperature range 280 K < T < 370 K, the total apparent mean-squared displacement ⟨ u2 ⟩ is recorded in solutions of bovine serum albumin by fixed-window neutron scattering. ⟨ u2 ⟩ increases monotonically with T below and above denaturation, whereas it decreases strongly at the denaturing transition. This observation can be rationalized and modeled as a transition from a liquid protein solution to a gel-like state. Atomic vibrations as well as librations and diffusion of the entire protein contribute to ⟨ u2 ⟩. The diffusion monitored by quasi-elastic neutron scattering [1,2] is consistent with a significant hindrance due to entanglement of the chains upon denaturing. The related pronounced decrease in ⟨ u2 ⟩ is analytically separated. Thus, we extract the purely intramolecular dynamics around the denaturing transition of freely diffusing proteins. This analysis introduces a general concept, which is applicable to other colloid systems exhibiting both center-of-mass and internal dynamics [1].
[1] M. Hennig et al., Soft Matter, DOI:10.1039/c1sm06609a;
[2] F. Roosen-Runge et al., PNAS 2011, 108:11815