Related Experiment Video
Updated: Feb 10, 2026

Atomic Force Microscopy Imaging and Force Spectroscopy of Supported Lipid Bilayers
Published on: July 22, 2015
Combined Recognition Imaging and Force Spectroscopy: A New Mode for Mapping and Studying Interaction Sites at Low
Melanie Koehler1, Gabriel Macher2, Anne Rupprecht2
1Institute of Biophysics, Johannes Kepler University, Linz, Gruberstraße 40, 4020 Linz, Austria.
Abstract:
We combined recognition imaging and force spectroscopy to study the interactions between receptors and ligands on the single molecule level. This method allowed the selection of a single receptor molecule reconstituted in a supported lipid membrane at low density, with the subsequent quantification of the receptor-ligand unbinding force. Based on atomic force microscopy (AFM) tapping mode, a cantilever tip carrying a ligand molecule was oscillated across a membrane. Topography and recognition images of reconstituted receptors were recorded simultaneously by analyzing the downward and upward parts of the oscillation, respectively. Functional receptor molecules were selected from the recognition image with nanometer resolution before the AFM was switched to the force spectroscopy mode, using positional feedback control. The combined mode allowed for dynamic force probing on different pre-selected molecules, resulting in higher throughput when compared with force mapping. We applied this method for a quantitative characterization of the binding mechanism between mitochondrial uncoupling protein 1 (UCP1) and its inhibitor adenosine triphosphate (ATP). Moreover the dynamics of force loading was varied to elucidate the binding dynamics and map the interaction energy landscape.
Related Concept Videos
Ligand Binding Sites
Protein-ligand interactions are quite specific; even though numerous potential ligands surround a cellular protein at any given time, only a particular ligand can bind to that protein. Moreover, a ligand binds only to a dedicated area on the surface of the protein, known as the...
Ligand Binding Sites
Conserved Binding Sites
Binding sites are often located in large pockets, and if their location on a protein’s surface is unknown, it can be predicted using various approaches. The energetic method computationally...
Intermolecular Forces
Interaction of EM Radiation with Matter: Spectroscopy
What is a Mode?
There can be more than one mode in a data set if multiple values have the same highest frequency. For instance, suppose that the Statistics exam scores of 20 students are: 50; 53; 59; 59; 63; 63; 72; 72; 72; 72; 72; 76; 78; 81; 83; 84; 84; 84; 90; 93. Here, the mode is 72, as it occurs most frequently, five times.
A data set with two modes is called bimodal. For example,...

