Dresden 2009 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
BP: Fachverband Biologische Physik
BP 12: Single Molecules
BP 12.10: Vortrag
Mittwoch, 25. März 2009, 12:30–12:45, HÜL 186
Calcium mediated carbohydrate-carbohydrate interactions investigated with single molecule force spectroscopy — •André Körnig1,2, Iwona Bucior3, Max M Burger4, Xavier Fernandèz-Busquets2, and Dario Anselmetti1 — 1Experimental Biophysics, Bielefeld University — 2Nanobioengineering Group, University of Barcelona — 3University of California, San Francisco — 4Friedrich-Miescher-Institute, Basel
Marine sponges associate through species-specific, calcium-mediated carbohydrate-carbohydrate interactions of the g200 glycan found on sponge proteoglycans. A detailed and quantitative single molecule force spectroscopy analysis of g200-g200 binding in Microciona prolifera reveals adhesion forces in the range of 100-250 pN. However, our results indicate that calcium-dependent, macroscopic sponge cell self-association is only little influenced by the absolute single molecule binding forces but critically rely on the kinetic reaction properties that manifest themselves in Ca2+-mediated bond lifetimes (10 mM Ca2+/ 0 mM Ca2+: 680 s / 3 s) and bond reaction lengths (10 mM Ca2+/ 0 mM Ca2+: 3.47 Å / 2.27 Å). Since cellular association in sponges is a polyvalent process, the observed binding phenomenon has to be analysed with a cooperative adhesion cluster model that distinctively supports the macroscopic observations of mean dissociation lifetimes for sponge multicell integrity in low and high calcium. A potential relation to a more generalized picture of the mid-cambrian explosion of metazoan evolution will be discussed.