The screening group is integral part of Chemical Biology Program efforts in identifying the selective small molecule ligands for human proteins with these main benefits:
- Tight-binding ligands have the potential to stabilize and solubilize proteins, reduce aggregation and thereby enhance crystallization success rates of SGC targets.
- Selective small molecule tools can facilitate target validation of proteins for therapeutic intervention, by probing their roles in biochemical processes related to disease.
Activities of the group are focused on:
- Assembly and curation of protein family focused compound libraries, driven by literature review, selection and purchase of commercially available compounds, and also augmented by synthesis of new compounds by Med-chem. group.
- Hit identification by in-house medium throughput screening of the libraries is combined with collaborations with high-throughput screening groups.
- Where possible, de novo design to accelerate hit identification.
- Screening of the followup compounds to identify the most appropriate hits for further study and, where necessary, generation of SAR to optimize physicochemical properties.
Main screening platforms:
Alpha screen
The name stands for Amplified Luminescent Proximity Homogeneous Assay. Binding of molecules captured on the beads leads to an energy transfer from one bead to the other, ultimately producing a luminescent/fluorescent signal. The assay can be used for studying the protein-protein interactions (PPI) as shown below. The PPI inhibitor will conceivably disrupt complex formation in concentration dependent manner resulting in the disappearance of the signal. Alternatively, assay can rely on the detection of the enzymatic reaction product. Addition of enzyme inhibitor will decrease the product production and again, the Alpha screen signal.
Differential Scanning Fluorimetry
aka Thermal Shift Assay. The assay principle is based on the stabilization of the native protein structure upon the ligand binding. The rank order of ligand binding and the estimate of the binding energy can be obtained by comparing the Tm values of the apo-protein and protein-ligand complexes:
Biolayer Interferometry.
This is a label-free direct detection method for study protein-protein and protein-ligand interaction. The applicability and information output is similar to surface plasmon resonance method. OctetRed384 is 16-channel medium to high throughput machine operating with 384-well sample plates.
