Related Experiment Video
Updated: May 30, 2026

Determination of Protein-ligand Interactions Using Differential Scanning Fluorimetry
Published on: September 13, 2014
Quantitative characterization of temperature-independent and temperature-dependent protein-protein interactions in
Adedayo A Fodeke1, Allen P Minton
1Section on Physical Biochemistry, Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, U.S. Department of Health and Human Services, Bethesda, Maryland 20892, USA.
Abstract:
The interaction among each of three dilute "tracer" proteins (bovine serum albumin, superoxide dismutase, and ovomucoid) at a concentration of 2 mg/mL and each of two "crowder" proteins (ovomucoid and BSA) at concentrations up to 100 mg/mL was characterized by analysis of dependence of the equilibrium gradients of both tracer and crowder upon the concentration of crowder. The equilibrium gradients of both crowder proteins were found to be independent of temperature over the range 5-37 °C. The equilibrium gradients of tracer BSA and ovomucoid in the complementary crowder species were likewise found to be independent of temperature over this range, indicating that interaction among these tracers and crowders is predominantly repulsive and essentially entirely entropic in nature. The equilibrium gradient of tracer SOD in BSA was also found to be independent of temperature over this range, but the gradient of tracer SOD in ovomucoid depended significantly upon temperature in a manner indicating a significant enthalpic (attractive) component of the overall interaction between SOD and ovomucoid. The experimental data are analyzed using model-free expansions of the thermodynamic activity coefficients of tracer and crowder in powers of the concentration of crowder and using approximate statistical thermodynamic models based upon highly simplified descriptions of molecular structure and interactions. Detailed analysis of the results indicates a relatively small contribution of nonspecific attraction to the total protein-protein interaction, which is dominated by steric repulsion.
More Related Videos
06:48Single-Molecule Measurement of Protein Interaction Dynamics Within Biomolecular Condensates
Published on: January 5, 2024
08:22Calibration-free In Vitro Quantification of Protein Homo-oligomerization Using Commercial Instrumentation and Free, Open Source Brightness Analysis Software
Published on: July 17, 2018
Related Concept Videos
Protein-protein Interfaces
Noncovalent Attractions in Biomolecules
Four types of noncovalent interactions are hydrogen bonds, van der Waals forces, ionic bonds, and hydrophobic interactions.
Hydrogen bonding results from the electrostatic attraction of a hydrogen atom covalently bonded to a strong-electronegative atom like oxygen,...
Protein Networks
These interactions can be represented through maps depicting protein-protein interaction networks, represented as nodes and edges. Nodes are circles that are representative of a protein,...
The Equilibrium Binding Constant and Binding Strength
Protein-Drug Binding: Determination Methods
Indirect methods involve isolating the bound drug from its free form in biological samples such as blood, serum, or plasma. These techniques aim to measure the percentage of drugs bound to proteins. Equilibrium dialysis is a commonly used method where the free drug concentration at equilibrium is measured by separating the bound...