Regensburg 2016 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
BP: Fachverband Biologische Physik
BP 58: Cytoskeletal Filaments
BP 58.6: Vortrag
Donnerstag, 10. März 2016, 11:00–11:15, H44
Small-Angle X-ray Scattering Investigation of Structural and Organizational Changes Induced by Ions on Keratin Filaments — •Clément Hémonnot1, Daniel Schmitz1, Manuela Denz1, Monika Mauermann2, Harald Herrmann2, and Sarah Köster1 — 1Institute for X-Ray Physics, Uni. Göttingen, Germany — 2DKFZ, Heidelberg, Germany
Keratin intermediate filaments (IF) proteins play an important role for cell mechanics as they form extended filaments (5 nm radius) and complex, highly ordered intracellular networks, which provide integrity and stability to epithelial cells. We present a study of the assembly of keratin in presence of monovalent and divalent ions by small-angle X-ray scattering (SAXS). As SAXS can reveal structures on the nanometer length scale, we investigate the impact of K+ and Mg2+ ions on the internal structure and organization of keratin filaments and assemblies. We show that the radius of the filaments follows a linear trend with increasing ion concentration. Moreover, we are able to determine where in the filaments the ions accumulate by using a model consisting of a core filament and Gaussian chains representing the N- and C- terminals. Because of Coulomb screening, at low concentrations both ion species accumulate in the side chains; at intermediate concentrations, the ions start to bind to the core of the filament; at high concentration, ions eventually lead to bundling events. Such bundling was not observed in the case of monovalent ions for other IFs such as vimentin. These results help to understand the differences in structure formation in different IFs, leading to different mechanical roles in the cell.