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Mechanically enforced bond dissociation reports synergistic influence of Mn2+ and Mg2+ on the interaction between integrin α7β1 and invasin

Authors

  • Agnieszka Ligezowska,

    1. Department of Physics, Jagiellonian University, 30-059 Cracow, Poland
    2. Institute for Physics and Chemistry, University of Southern Denmark, DK-5230 Odense M, Denmark
    3. Center for Molecular Medicine, Vascular Matrix Biology, Excellence Cluster Cardio-Pulmonary System, Frankfurt University, D-60590 Frankfurt am Main, Germany
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  • Kristian Boye,

    1. Institute for Physics and Chemistry, University of Southern Denmark, DK-5230 Odense M, Denmark
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  • Johannes A. Eble,

    1. Center for Molecular Medicine, Vascular Matrix Biology, Excellence Cluster Cardio-Pulmonary System, Frankfurt University, D-60590 Frankfurt am Main, Germany
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  • Bernd Hoffmann,

    1. Institute of Bio- and Nanosystems, Forschungszentrum Jülich, D-52425 Jülich, Germany
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  • Beate Klösgen,

    1. Institute for Physics and Chemistry, University of Southern Denmark, DK-5230 Odense M, Denmark
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  • Rudolf Merkel

    Corresponding author
    1. Institute of Bio- and Nanosystems, Forschungszentrum Jülich, D-52425 Jülich, Germany
    • Institute of Bio- and Nanosystems, Forschungszentrum Jülich, D-52425 Jülich, Germany.
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  • A. L. and K. B. contributed equally to this project.

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 α7β1 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. Copyright © 2011 John Wiley & Sons, Ltd.

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