Force spectroscopy of barnase–barstar single molecule interaction

Authors

  • S. K. Sekatskii,

    Corresponding author
    1. Laboratoire de Physique de la Matière Vivante, IPMC, BSP, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
    • Laboratoire de Physique de la Matière Vivante, IPSB, BSP, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
    Search for more papers by this author
  • M. Favre,

    1. Laboratoire de Physique de la Matière Vivante, IPMC, BSP, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
    Search for more papers by this author
  • G. Dietler,

    1. Laboratoire de Physique de la Matière Vivante, IPMC, BSP, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
    Search for more papers by this author
  • A. G. Mikhailov,

    1. M. M. Shemyakin and Yu. V. Ovchinnikov Institute of Bioorganic Chemistry Russian Academy of Sciences, 119991 Moscow, Russia
    Search for more papers by this author
  • D. V. Klinov,

    1. M. M. Shemyakin and Yu. V. Ovchinnikov Institute of Bioorganic Chemistry Russian Academy of Sciences, 119991 Moscow, Russia
    Search for more papers by this author
  • S. V. Lukash,

    1. M. M. Shemyakin and Yu. V. Ovchinnikov Institute of Bioorganic Chemistry Russian Academy of Sciences, 119991 Moscow, Russia
    Search for more papers by this author
  • S. M. Deyev

    1. M. M. Shemyakin and Yu. V. Ovchinnikov Institute of Bioorganic Chemistry Russian Academy of Sciences, 119991 Moscow, Russia
    Search for more papers by this author

  • This article is published in Journal of Molecular Recognition as a special issue on Affinity 2009, edited by Gideon Fleminger, Tel-Aviv University, Tel-Aviv, Israel and George Ehrlich, Hoffmann-La Roche, Nutley, NJ, USA.

Abstract

Results of the single molecule force spectroscopy study of specific interactions between ribonuclease barnase and its inhibitor barstar are presented. Experimental data obtained for the force loading rate ranging 2–70 nN/s are well approximated by a single straight line, from which the dissociation barrier of the width of 0.12 nm and height of 0.75–0.85×10−19 J can be inferred. The measured value of specific interaction does not depend on the NaCl concentration. This apparently contradicts the well-known dependence of the binding energy of this pair on the salt concentration, but such a “contradiction” is explained by the insensitivity of the force spectroscopy data to the relatively long-range electrostatic interaction. The latter essentially contributes to the value of barnase–barstar binding energy revealed by biochemical measurements, and it is exactly this electrostatic interaction which is influenced by the salt concentration. Copyright © 2010 John Wiley & Sons, Ltd.

Ancillary