Functional Application Areas

Binding Studies with Differential Scanning Calorimetry (DSC)

Differential Scanning Calorimetry (DSC) is primarily used to characterize stability and folding.  When a small molecule ligand preferentially binds to the native form of a protein, the ligand stabilizes the protein and the Tm of the protein-ligand complex is higher than that of the protein in the absence of ligand. If the ligand preferentially binds to the denatured protein, the Tm decreases in the presence of the ligand. DSC is used to measure the binding constants from Tm shifts due to drug (or other small molecule) binding to a protein (Figure 1). The binding constant of the ligand can be estimated from the Tms in the presence and absence of ligand, as long as the concentration of ligand in the DSC cell is known. This method can estimate binding constants up to 1020 M-1. It can be used for ligands with ultratight binding constants that cannot be measured by other methods, as well as a screening assay for drug discovery.

Figure 1. The effect of adding different anionic inhibitors to Ribonuclease A (0.09mM).

References

Study of strong to ultratight protein interactions using differential scanning calorimetry.
Brandts, J.F., Lin, L.-N.
Biochemistry 29, 6927-6940 (1990)

Differential scanning microcalorimetry,
Cooper, A., Nutley, M.A., Wadood, A.
in Protein-Ligand Interactions: Hydrodynamics and Calorimetry.
Harding, S.E., Chowdhry, B.Z., eds.,
Oxford University press, Oxford UK, pp 287-318 (2001)

An autosampling differential scanning calorimeter instrument for studying molecular interactions.
Plotnikov, V., Rochalski, A., Brandts, M., Brandts, J.F., Williston, S., Frasca, V., Lin, L.-N.
Assay Drug Devel. Technol. 1, 83-90 (2002)

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