Albert-Ludwigs-Universität Freiburg

3 ARTICLES PUBLISHED IN JoVE

Engineering

Investigating Single Molecule Adhesion by Atomic Force Spectroscopy

Frank W. S. Stetter^1,2, Sandra Kienle^1,2, Stefanie Krysiak^1,2, Thorsten Hugel^1,2

¹Physik-Department E22a, Technische Universität München, ²IMETUM, Technische Universität München

A protocol to couple a large variety of single molecules covalently onto an AFM tip is presented. Procedures and examples to determine the adhesion force and free energy of these molecules on solid supports and bio-interfaces are provided.

Biochemistry

Using Three-color Single-molecule FRET to Study the Correlation of Protein Interactions

Markus Götz¹, Philipp Wortmann¹, Sonja Schmid^1,2, Thorsten Hugel¹

¹Institute of Physical Chemistry, University of Freiburg, ²Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology

Here, we present a protocol to obtain three-color smFRET data and its analysis with a 3D ensemble Hidden Markov Model. With this approach, scientists can extract kinetic information from complex protein systems, including cooperativity or correlated interactions.

Chemistry

Covalent Attachment of Single Molecules for AFM-based Force Spectroscopy

Adrianna Kolberg¹, Christiane Wenzel¹, Thorsten Hugel^1,3, Markus Gallei², Bizan N. Balzer^1,3

¹Institute of Physical Chemistry, Albert-Ludwigs-Universität Freiburg, ²Chair in Polymer Chemistry, Saarland University, ³Cluster of Excellence livMatS at FIT - Freiburg Center for Interactive Materials and Bioinspired Technologies, University of Freiburg

Covalent attachment of probe molecules to atomic force microscopy (AFM) cantilever tips is an essential technique for the investigation of their physical properties. This allows us to determine the stretching force, desorption force and length of polymers via AFM-based single molecule force spectroscopy with high reproducibility.