Colloquium 6/27/2011

Frank Schreiber, Institute for Applied Physics, Universität Tübingen

Manipulating protein interactions with multivalent ions: Aggregation, crystallization and diffusion

After a brief review of interactions in protein solutions, we will discuss how multivalent ions can be used to manipulate these interactions and the associated phase behavior as well as the diffusion dynamics.

We show that multivalent ions do not only influence the ionic strength and the effective interactions in aqueous solutions [1], but lead to new effects.

We focus on results obtained by scattering (SAXS, ASAXS, SANS). Particular attention will be given to the "reentrant condensation" of proteins [2] and its relationship with liquid-liquid phase separation and crystallization. In particular, we attempt to rationalize crystallization controlled by trivalent ions [3].

These results are compared to the diffusion dynamics in these systems studied using neutron spectroscopy (QENS) and light scattering techniques (DLS).

References

1. F. Zhang et al., J. Phys. Chem. B 111 (2007) 251.
2. F. Zhang et al., Phys. Rev. Lett. 101 (2008) 148101; F. Zhang et al., Proteins: Structure, Function, and Bioinformatics, 78 (2010) 3450.
3. F. Zhang et al., J. Appl. Cryst., in print.
4. F. Roosen-Runge et al., PNAS, in print.
5. F. Zhang, M. W. A. Skoda, R. M. J. Jacobs, S. Zorn, R. A. Martin, C. M. Martin, G. F. Clark, S. Weggler, A. Hildebrandt, O. Kohlbacher, and F. Schreiber. Reentrant condensation of proteins in solution induced by multivalent counterions, Phys. Rev. Lett. 101 (2008) 148101. http://www.soft-matter.uni-tuebingen.de/publications/Zhang_prl08.pdf
6. F. Zhang, S. Weggler, M. J. Ziller, L. Ianeselli, B. S. Heck, A. Hildebrandt, O. Kohlbacher, M. W. A. Skoda, R. M. J. Jacobs, and F. Schreiber. Universality of protein reentrant condensation in solution induced by multivalent metal ions, Proteins: Structure, Function, and Bioinformatics 78 (2010) 3450. http://www.soft-matter.uni-tuebingen.de/publications/Zhang_proteins10.pdf
7. F. Zhang, G. Zocher, A. Sauter, Th. Stehle, and F. Schreiber. Novel approach to controlled protein crystalization through ligandation of yttrium cations. J. Appl. Cryst., in print. http://www.soft-matter.uni-tuebingen.de/publications/Zhang_jac11_preprint.pdf
8. Felix Roosen-Runge, Marcus Hennig, Fajun Zhang, Robert M.J. Jacobs, Michael Sztucki, Helmut Schober, Tilo Seydel, and Frank Schreiber. Protein Self-Diffusion in Crowded Solutions. PNAS, in print. https://mailout.ill.fr/attach/download.php?uoy=MWY3MzQ1ZDVkNGZkZmQ3Yjg3N2NhZjQwZTc1Yzc1OWI=