Related Experiment Video
Updated: Jul 12, 2026

Bio-layer Interferometry for Measuring Kinetics of Protein-protein Interactions and Allosteric Ligand Effects
Published on: February 18, 2014
Evidence for fast conformational change upon ligand dissociation in the HemAT class of bacterial oxygen sensors
Audrey Mokdad1, Mark Nissen, James D Satterlee
1Department of Chemistry, University of South Florida, 4202 East Fowler Ave., Tampa, FL 33620, United States.
Abstract:
Here we report the results of transient absorption and photoacoustic calorimetry studies of CO photodissociation from the heme domain of the bacterial oxygen sensor HemAT-Bs. The results indicate that CO photolysis is accompanied by an overall DeltaH of -19 kcal mol(-1) and DeltaV of +4 ml mol(-1) as well as a red-shifted kinetic difference spectrum all occurring in <50 ns. Analysis of the DeltaH/DeltaV reveals that a conformational change takes place with a DeltaH(conf) of -40 kcal mol(-1) and DeltaV(conf) of -22 ml mol(-1). These thermodynamic changes are consistent with an increase in the solvent accessible surface area of the protein upon ligand dissociation, as observed in the X-ray structure of the ferric CN-bound and CN free forms of HemAT-Bs.
Related Concept Videos
Cooperative Allosteric Transitions
Gene Families
Occasionally these regions can be adapted to take on new roles within the organism, becoming novel genes...
Oxygen Transport in the Blood
Global Regulatory Systems
Protein and Protein Structure
A protein's shape is critical to its function. For example, an enzyme can...
Ligand Binding and Linkage

