Regensburg 2019 – scientific programme
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BP: Fachverband Biologische Physik
BP 26: Single molecules biophysics
BP 26.2: Talk
Thursday, April 4, 2019, 15:30–15:45, H4
AFM-based Single-Molecule Force Spectroscopy on the Streptavidin:Biotin Interaction — •Steffen M. Sedlak1, Leonard C. Schendel1, Katherine R. Erlich1, Achim Löf1, Rafael C. Bernardi2, Magnus S. Bauer1, Carleen Kluger1, and Hermann E. Gaub1 — 1Department of Physics and Center for NanoScience, LMU Munich, Germany — 2University of Illinois at Urbana-Champaign, Urbana, IL, USA
The high-affinity interaction of the small molecule biotin with the tetrameric protein streptavidin (SA) is a widely applied tool for detection, labeling and immobilization of molecules. We study single biotin:SA interactions under force using AFM-based single-molecule force-spectroscopy (SMFS) and steered Molecular Dynamics (sMD) simulations. Probing monovalent SA in various specific tethering geometries, we investigated how the mechanical stability of the biotin:SA interaction depends on the force loading geometry and revealed the underlying molecular mechanism. We made use of the different unbinding forces to realize a protein-based bottom-up nanoscale assembly of single fluorescent molecules by single-molecule cut-and-paste; a unique approach that enables spatially controlled arrangements of diverse molecules into a single ensemble. We also studied SA of different valencies and distinguished unbinding forces of biotin from different SA subunits in AFM-based SMFS. sMD allowed to understand the force-propagation pathways through the SA tetramer. Identifying a long-lived tethering geometry, we can reliably measure single molecules at comparably high constant forces for many hours in magnetic tweezers.