title: Mechanically enforced bond dissociation reports synergistic influence of Mn2+ and Mg2+ on the interaction between integrin α7β1 and invasin.
abstract: Integrins require the divalent ions magnesium and manganese for ligand recognition. Here we mechanically enforced bond dissociation to explore the influence of these ions on the mechanical strength of the specific bond between α(7) β(1) integrin and its pathologically relevant ligand invasin. Upon addition of these cations to the measurement buffer, we observe a pronounced increase in the force necessary to separate integrin and invasin coated beads. Both ions were found to work synergistically. With free invasin in the measurement buffer we furthermore observe that competitive blocking of binding sites overrides the increase in binding strength of individual beads. We show that this is due to a very strong dependence of bond affinity on divalent ions. Our study illustrates the importance of divalent ions for the regulation of force transmission by integrin ligand bonds on the molecular level.
authors.affiliation: Department of Physics, Jagiellonian University, 30-059 Cracow, Poland.
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Ligezowska
authors.forename: Kristian
authors.initials: K
authors.lastname: Boye
authors.forename: Johannes A
authors.initials: JA
authors.lastname: Eble
authors.forename: Bernd
authors.initials: B
authors.lastname: Hoffmann
authors.forename: Beate
authors.initials: B
authors.lastname: Klösgen
authors.forename: Rudolf
authors.initials: R
authors.lastname: Merkel
mesh_terms: D018829:Adhesins, Bacterial / Q000378:metabolism*; D016023:Integrins / Q000378:metabolism*; D008274:Magnesium / Q000494:pharmacology*; D008345:Manganese / Q000494:pharmacology*; D011485:Protein Binding / Q000187:drug effects
chemical_list: D018829:Adhesins, Bacterial; D016023:Integrins; C053476:invasin, Yersinia; D008345:Manganese; D008274:Magnesium; C082908:integrin alpha7beta1