Regensburg 2019 – scientific programme

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BP: Fachverband Biologische Physik

BP 12: Poster II

BP 12.72: Poster

Tuesday, April 2, 2019, 14:00–16:00, Poster B2

Comparing the Mechanical Strengths of the Interaction of Biotin with Avidin-like proteins by AFM-based Single Molecule Force Spectroscopy — •Jonas C. Fischer, Steffen M. Sedlak, Leonard C. Schendel, Philipp R. Müller, Magnus S. Bauer, Carleen Kluger, and Hermann E. Gaub — Department of Physics and Center for NanoScience, LMU Munich, Germany

Avidin-like proteins are a wildly applied tool in nano- and biotechnology for immobilization, labeling and detection of molecules.

Here, we investigate the interaction of the tetrameric proteins streptavidin, traptavidin and streptactin with the small molecule biotin by AFM-based Single-Molecule Force Spectroscopy. Site-specific and covalent immobilization of different receptor molecules on the same surface enables stable and parallel long-term measurements of unbinding events. By the use of fingerprint domains providing characteristic unfolding patterns true single-molecule interactions are identified.

Both traptavidin and streptactin differ from wild-type streptavidin from Streptomyces avidinii only by three amino acids. The unbinding force of biotin from streptavidin is strongly dependent on tethering geometry. The rupture forces for the C-terminal anchoring is about two times higher as for N-terminal attachment. While traptavidin behaves in a similar manner, the rupture forces for streptactin differ: We observe a loading rate dependent transition from a low force binding to a high force binding state.