Regensburg 2016 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 10: Colloids and Complex Fluids III (Joint Session CPP/DY/BP)
BP 10.9: Vortrag
Montag, 7. März 2016, 17:15–17:30, H42
Clusters of proteins – are they transient or static? — •Michal Braun1, Marco Grimaldo1,2, Felix Roosen-Runge2, Christian Beck1, Fajun Zhang1, Frank Schreiber1, and Tilo Seydel2 — 1Institut für Angewandte Physik, Universität Tübingen, Germany — 2Institut Laue-Langevin, Grenoble, France
Signatures of protein clusters have been observed for globular proteins such as lysozyme [1], crystallins and bovine serum albumin [2,3]. The nature of these clusters, whether static or transient, however, is still a debated question and depends sensitively on environmental conditions. A better understanding would be key to use protein clusters as precursors for protein crystallization or in drug delivery.
We report cluster formation in solutions of β-lactoglobulin (BLG), as systematically investigated using static and dynamic scattering techniques. From small-angle scattering (SAXS/SANS), we obtain a cluster signature from the missing shift of the correlation peak with concentration and related data fitting. Neutron quasi-elastic backscattering (QENS) evidences the formation of oligomers via the short-time self-diffusion coefficient at nanosecond time scales. Finally, neutron spin-echo spectroscopy (NSE) allows to compare structural information from the structure factor with the dynamical features of collective diffusion on time scales of several tens of nanoseconds, which ultimately allows to determine the nature of the observed protein clusters.
[1] Stradner et al. Nature 432 (2004) 492
[2] Soraruf et al. Soft Matter 10 (2014) 894
[3] Grimaldo et al. J. Phys. Chem. Lett. 6 (2015) 2577