Regensburg 2013 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 8: Posters: Proteins

BP 8.10: Poster

Montag, 11. März 2013, 17:30–19:30, Poster B2

Self-diffusion of proteins in solution close to a salt-induced phase transition — •Marco Grimaldo.¹, Vincent Glenisson^1,2, Marcus Hennig¹, Felix Roosen-Runge¹, Fajun Zhang¹, Tilo Seydel², and Frank Schreiber¹ — ¹Fakultät für Physik - Universität Tübingen, Auf der Morgenstelle 10, D-72076 Tübingen, Germany — ²Institut Laue-Langevin, B.P. 156, F-38042 Grenoble, France

A reentrant phase diagram is observed in aqueous solutions of Bovine Serum Albumin (BSA) upon addition of a trivalent salt (Yttrium Chloride) at concentration c_s . In particular, increasing c_s for a certain protein concentration c_p, a phase transition occurs at a characteristic concentration c_s^*. For c_s > c_s^* macroscopic aggregates form [1]. Measurements on the neutron backscattering spectrometers IN10 and IN16 at the Institute Laue-Langevin have shown that the short time self-diffusion of the proteins in such system decreases when c_s approaches c_s^*. For a better understanding of this phenomenon, data has been collected also with the backscattering spectrometer BASIS (SNS, ORNL) in order to increase the accessible time scales. In presenting the data analysis we will also discuss the method adopted to obtain consistent results from different quasi-elastic neutron scattering (QENS) instruments.

[1] Zhang et al. PRL 101 (2008) 148101

[2] Roosen-Runge et al. PNAS 108 (2011) 11815