Dresden 2009 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 17: Poster II
BP 17.7: Poster
Mittwoch, 25. März 2009, 17:15–19:45, P3
Influence of Mn2+ and Mg2+ on the interaction between integrin α7β1 and invasin studied by dynamic force spectroscopy — •Agnieszka Ligezowska1, Kristian Boye2, Johannes Eble3, Bernd Hoffmann4, Beate Klösgen2, and Rudolf Merkel4 — 1Department of Physics, Jagiellonian University, Cracow, Poland — 2Memphys Center for Biomembrane Physics, University of Southern Denmark, DK-5230 Odense, Denmark — 3Institut für Physiologische Chemie und Pathobiochemie, Westfälische Wilhelms-Universität Münster, D-48149 Münster, Germany — 4Institut für Bio- und Nanosysteme, Forschungszentrum Jülich, D-52425 Jülich, Germany
The ligand binding function of integrins, a group of transmembrane proteins mediating cell-matrix adhesion in animals, is known to be influenced by divalent cations. We have applied the Biomembrane Force Probe technique to study this phenomenon for a soluble variant of integrin α7β1 and one of its ligands, invasin 497, an outer membrane protein of Yersinia bacteria. In a dynamic force spectroscopy approach, we show that the binding affinity of α7β1 is promoted by divalent manganese and magnesium ions and that these ions work to enforce the binding strength in a synergistic manner. Single bond events could be studied by successive addition of free invasin to the measurement buffer which reduced the number of available binding sites and thus diminished the likelihood of multiply bond formation. Combining force-induced bond dissociation with free ligand binding enabled simultaneous studies of Mn2+ and Mg2+ influence in both, equilibrium and non-equilibrium conditions.