Regensburg 2019 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 32: Charged Soft Matter, Polyelectrolytes and Ionic Liquids I
CPP 32.4: Vortrag
Mittwoch, 3. April 2019, 10:15–10:30, H13
Competing interactions and the formation of dynamic protein clusters — •Anita Girelli1, Michal K. Braun1, Alessandro Marianini2, Fajun Zhang1, and Frank Schreiber1 — 1Universität Tübingen, Germany — 2ESRF Grenoble, France
Controlling of cluster formation is of high relevance in biology, biomedicine and pharmacy. In this study solutions of bovine serum albumin with LaCl3 were studied using small angle x-ray scattering (SAXS) and dynamic light scattering (DLS) to characterize the static and dynamic properties of protein clusters. The system has a reentrant phase behavior [1], before the system enters the condensation regime the presence of long range repulsion and short range attraction leads to the cluster formation [2]. DLS and SAXS data suggest the formation of clusters for a ratio of salt and protein concentration cs/cp>3, supported also by neutron backscattering experiments [3]. The SAXS data for samples with a series of concentrations were fitted with a law qc=aφb, where φ is the volume fraction and qc the position of the correlation peak present in the structure factor. The parameter b was found to have a value larger than 1/3. Based on geometrical consideration this suggest that the number of clusters decreases for increasing protein concentration. This could be attributed to an entropic effect or to an increase of ionic strength.
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