Regensburg 2013 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

BP: Fachverband Biologische Physik

BP 28: Focus session: Intracellular Spectroscopy

BP 28.3: Vortrag

Donnerstag, 14. März 2013, 10:15–10:30, H44

Protein motion in crowded solutions on fast time scales: diffusion and internal dynamics — •Felix Roosen-Runge¹, Marcus Hennig^1,2, Fajun Zhang¹, Tilo Seydel², and Frank Schreiber¹ — ¹Institut für Angewandte Physik, Universität Tübingen — ²Institut Laue-Langevin, Grenoble, France

Protein function depends on the complex interplay of structure, dynamics and the aqueous, but crowded cellular environment. We present a comprehensive experimental study accessing the full hierarchy of protein dynamics in solutions, e.g. vibrations, interdomain motions and diffusion of the entire protein. Quasi-elastic neutron and dynamic light scattering experiments have been performed and compared to theoretical predictions. In crowded solutions, both self diffusion D_s and collective diffusion D_c of protein solutions are well described by colloidal concepts, with D_s reduced to 20 % at ≈ 20 % volume fraction [1,2]. Separating the motion of the entire protein molecule, the internal motions are accessed under native conditions [3]. We studied the dynamics before, during and after thermal denaturation, supporting the notion of protein unfolding with subsequent chain entanglement. In the denatured, gel-like state, long-range motions are strongly reduced, while the local flexibility is enhanced. Using the analysis frameworks, neutron backscattering is well-suited to address the relation of protein function and dynamics under native conditions at fast time scales.

[1] F. Roosen-Runge, M. Hennig et al., PNAS 108 (2011) 11815; [2] M. Heinen, F. Zanini et al., Soft Matter 8 (2012) 1404; [3] M. Hennig, F. Roosen-Runge et al., Soft Matter 8 (2012) 1628