Regensburg 2019 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 12: Poster II

BP 12.71: Poster

Dienstag, 2. April 2019, 14:00–16:00, Poster B2

Influence of Ligand Binding on the Mechanical Stability of a Single Protein Revealed by AFM-based Force Spectroscopy — •Philipp R. Müller, Steffen M. Sedlak, Leonard C. Schendel, Jonas C. Fischer, Magnus S. Bauer, Carleen Kluger, and Hermann E. Gaub — Department of Physics and Center for NanoScience, LMU Munich, Germany

AFM-based force spectroscopy enables a large number of measurements of individual proteins. Covalent and site-specific immobilization strategies are key for consistent and reproducible force spectroscopy data. Fingerprint domains that exhibit a characteristic unfolding pattern serve as internal force reference and to reliably identify single-molecule interactions.

Streptavidin (SA) is a tetrameric protein that is frequently used in force spectroscopy experiments and binds biotin, as well as desthiobiotin and Strep-tag II with high affinity.

Here, we investigate the effect of ligand binding on the mechanical stability of a single SA subunit. In a tetrameric SA, we tether one of the four SA subunits by its C- and N-terminus and unfold it in the presence and absence of different ligands. Furthermore, combining functional and non-functional SA subunits, which cannot bind any ligands, we are able to create SA of different valencies in a controlled way. Using these SA variants, we analyze the influence of different ligands, binding to the tethered or the neighboring subunit, on the mechanical stability of the molecule. Unfolding patterns and rupture forces depend on the type of ligand employed.