Biophysical assays are the ideal photon-based assay companion. In fact, while they often lack the throughput required for a primary readout (though some recent advances are pushing old boundaries), they allow label-free detection where the measurement directly corresponds to a biophysical variation. Thus, they are not only an orthogonal measurement, but also enable the understanding and rationalization of additional parameters such as thermodynamic, kinetics and structural information.
We have a set of biophysical tools available that allow, for example, the determination of binding kinetics, affinity and specificity, secondary structure and thermodynamic profiles, or structural insights on the molecular interactions of a small molecule or a peptide to its target.
Nuclear Magnetic Resonance (NMR) spectroscopy is a powerful tool for the study of structural biology, structure/activity relationships and macromolecule and small-molecule analysis. Our NMR team is highly experienced in both small molecule and macromolecule analysis. Through the use of chemical shift mapping and saturation transfer difference (STD) experiments we offer fast insights into the way a ligand interacts with its target, both in terms of binding site and binding mode. This information can be used to validate hits or during the lead optimization phase.
Circular dichroism spectroscopy
Circular dichroism (CD) spectroscopy is a measurement of the difference in absorbance of right and left-circularly polarized light. CD is a powerful tool for studying peptide and protein conformation requiring a minimal amount of sample compared to other techniques. CD spectra in the far UV range report for secondary structures while in the near UV they are characteristics of the tertiary structure of proteins.
To support our discovery programs we can use CD spectroscopy for different applications for the study of secondary structure content of peptides and proteins, monitoring conformational transitions, and the study of the thermodynamics of unfolding and protein-ligand interactions.
We use multiple types of mass spectrometry methods; most commonly liquid chromatography-high-resolution OrbiTrap mass spectrometry (LC-HRMS) to analyse both biochemical and cell based assays. In biochemical studies, mass spectrometry is used for enzyme activity measurement by product/substrate detection or determination or for the measurement of covalent binding. Alternatively, in cells, HRMS data are acquired using quantitative/qualitative analysis to allow quantifying the increase/decrease of cellular metabolites of interest to validate the mechanism of action of compound directed against metabolic pathways.
Surface plasmon resonance
At IRBM, we have an established expertise in SPR technology and we consider SPR an indispensable tool for drug discovery. The fast and real time analysis of the kinetic and thermodynamic binding parameters of small molecules, peptides, antibodies, or other protein-protein interactions, are crucial information for target characterization, hit identification, lead optimization or characterization of the binding properties of a molecule to its target. Furthermore, thanks to its sensitivity, only small volumes of samples are required, making SPR suitable to any screening campaign.
Bio-Layer Interferometry (BLI) based biosensor technology is a powerful tool to measure molecular interactions in real time. Due to its great flexibility, it allows us to detect, quantify and determine the kinetics of biomolecule interactions even in different types of complex biological matrixes. At IRBM, we rely on BLI for antibody and small molecule screening when high throughput is needed. We consider it as a must-to-have tool in all antibody development campaigns for fast and reliable hit screening based on affinity and hit clustering based on epitope binning.