Dresden 2009 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 22: Transport Processes and Cellular Trafficking
BP 22.7: Vortrag
Donnerstag, 26. März 2009, 16:15–16:30, ZEU 260
Protein diffusion in crowded solutions: A quasi-elastic neutron scattering study — •Felix Roosen-Runge1,2, Marcus Hennig1,2, Fajun Zhang1, Stefan Zorn1, Maximilian Skoda3, Robert M.J. Jacobs4, Tilo Seydel2, and Frank Schreiber1 — 1Institut für Angewandte Physik, Universität Tübingen, Germany — 2Institut Laue-Langevin, Grenoble, France — 3ISIS, Didcot, UK — 4Chemistry Research Laboratory, Oxford, UK
In a typical living cell, proteins function in a relatively crowded cytoplasmic environment where up to 40% of the space is occupied by various biomacromolecules. We present a quasi-elastic neutron scattering (QENS) study of protein dynamics under the condition of "protein crowding" in solution. Using the protein bovine serum albumin (BSA) as model, we studied the protein dynamics as a function of protein concentration, ionic strength and temperature in order to address self-diffusive motions on nanosecond time scales. The dynamics was studied by neutron backscattering scans performed at selected temperatures ranging from 280K up to 325K. The relaxation times and diffusion coefficients extracted from the fits for various states of the BSA solution (temperature, BSA and salt concentration) are analyzed. It was found that salt addition has no significant effect on the relaxation rates on length scales commensurate with protein nearest-neighbor distances, whilst temperature has a strong effect on the diffusive motion of BSA. Charge effects including ionic strength and valence are further addressed by complementary SAXS data.