Binding Affinity Measurement

Binding affinity measurement is a key step in the PROTAC scheme design. Profacgen provides a variety of detection methods.

Surface plasmon resonance (SPR) is the resonance oscillation at the interface between negative and positive dielectric constant materials excited by incident light. SPR is the basis of many standard tools for measuring the adsorption of materials on flat metal (usually gold or silver) surfaces or metal nanoparticles. This is the basic principle behind many color-based biosensors applications, different chip laboratory sensors and diatom photosynthesis.

Isothermal titration calorimetry (ITC) is a physical technique used to determine the thermodynamic parameters of interactions in solutions. It is most commonly used to study the binding of small molecules (such as medicinal compounds) to large molecules (proteins, DNA, etc.). It consists of two units enclosed in an insulating jacket. The compound to be studied is placed in a sample cell, while another cell (reference cell) is used as a control and contains a buffer in which the sample is dissolved.

Bilayer interferometry (BLI) is a label free technique for measuring biomolecular interactions. This is an optical analysis technique used to analyze the interference pattern of white light reflected from two surfaces. Any change in the number of molecules bound to the tip of the biosensor will lead to a change in the interference mode, which can be measured in real time. The combination of the ligand fixed on the tip surface of the biosensor and the analyte in the solution increases the optical thickness of the tip of the biosensor, resulting in a wavelength shift Δ λ, which is a direct measure of the thickness change of the biological layer. Interactions are measured in real time, enabling the monitoring of binding specificity, association and dissociation rates or concentrations with high accuracy and accuracy.

Microscale thermophoresis (MST) is a technique for biophysical analysis of biomolecular interactions. MST is based on the detection of temperature induced target fluorescence changes as a function of the concentration of non-fluorescent ligands. The observed fluorescence changes are based on two different effects. On the one hand, it is based on the temperature dependent intensity change of the fluorescent probe, which may be affected by binding events. On the other hand, it is based on thermophoresis, which is the directional movement of particles in the micro temperature gradient. Any change in the chemical microenvironment of the fluorescent probe, as well as the change in the hydrated shell of the biomolecule, will lead to a relative change in the fluorescence detected when the temperature gradient is applied, and can be used to determine the binding affinity. MST allows the interaction to be measured directly in solution without immobilization on the surface (no immobilization technique).

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