Protein folding intermediates probed by ensemble of their transient stiffnesses in single-molecule force-quenched AFM

ORAL

Abstract

By using force-quench AFM (FQ-AFM) spectroscopy molecular structures with transient stiffnesses are detected during folding of a recombinant protein with four I27 molecules linked in tandem. The intermediate stiffnesses are detected from shape and peaks of the autocorrelation of fluctuations in end-to-end lengths of the folding molecules, as well as by applying the equipartition theorem to the FQ-AFM experimental results. In the light of the relevant molecular dynamics simulations these intermediates are likely to probe the ensemble of random-coiled collapsed states present both in the force-quench and thermal-quench folding pathways.

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Authors

  • Robert Szoszkiewicz

    Kansas State University

  • Jatinder Kumar

    Harvard U., Baker University, Bejing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Northrop Grumman, Baltimore, MD, University of Kansas Dept. of Physics \& Astronomy, Kansas State University, Department of Chemistry, College of Materials Science \& Engineering, Sichuan University, China, Illinois State University, Mullard Space Science Laboratory, University College of London, Holmbury St. Mary, United Kingdom, Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO, United States, Weizmann Institute of Science, Rehovot, Israel, Monmouth College, Missouri State University, Birla Institute of Technology and Science, University of Illinois at Urbana Champaign, Ames Laboratory. Department of Physics and Astronomy, Iowa State University, Siena College, \'Ecole Polytechnique F\'ed\'erale de Lausanne, Switzerland, Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Kansas State University, Purdue University, Princeton University, Oklahoma State University, University of Chicago, University of Iowa, University of Kansas, University of Kansas and University of Iowa