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Updated: Feb 20, 2026
10:58
Protein WISDOM: A Workbench for In silico De novo Design of BioMolecules
Published on: July 25, 2013
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Improved Free-Energy Landscape Quantification Illustrated with a Computationally Designed Protein-Ligand Interaction
William J Van Patten1, Robert Walder1, Ayush Adhikari1
1JILA, National Institute of Standards and Technology and the University of Colorado, Department of Physics and Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, 440 UCB, Boulder, CO, 80309-0440, USA.
Summary
An enhanced atomic force microscopy (AFM) assay provides a detailed view of protein-ligand interactions. This method quantifies the energy landscape, offering deeper insights into molecular recognition beyond traditional parameters.
Area of Science:
- Biophysics
- Molecular Biology
- Biochemistry
Background:
- Understanding protein-ligand interactions is crucial for molecular recognition.
- Atomic force microscopy (AFM)-based force spectroscopy is a key single-molecule technique for studying these interactions.
- Traditional AFM methods typically provide dissociation rate constants (koff) and transition state distances (Δx≠).
Purpose of the Study:
- To introduce an enhanced AFM assay for more comprehensive analysis of protein-ligand binding energy landscapes.
- To apply this enhanced assay to the DIG10.3 protein and its ligand, digoxigenin.
- To obtain a more complete description of the energy landscape governing molecular recognition.
Main Methods:
- Utilized an enhanced atomic force microscopy (AFM) assay.
- Applied force spectroscopy to probe the binding of computationally designed protein DIG10.3 to digoxigenin.
- Analyzed high-quality data to extract detailed energy landscape parameters.
Main Results:
- The enhanced AFM assay yielded traditional parameters: dissociation rate constant (koff = 4±0.1×10⁻⁴ s⁻¹) and transition state distance (Δx≠ = 8.3±0.1 Å).
- Additionally, the study determined the transition state energy barrier height (ΔG≠ = 6.3±0.2 kcal mol⁻¹) and its shape (linear-cubic).
- Enhanced data quality enabled a more complete characterization of the binding energy landscape.
Conclusions:
- The developed automated and rapid AFM assay offers a more complete energy landscape description of protein-ligand interactions.
- This technique advances the study of molecular recognition by providing richer biophysical data.
- The enhanced assay is broadly applicable to diverse systems studied using AFM-based force spectroscopy.
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