Membrane proteins and especially so called G-Protein Coupled Receptors (GPCRs) represent the most important drug targets. Despite their importance they belong still to the most challenging drug targets.
InSingulos proprietary single molecule surface-sensitive microscopy-based method contributes to this challenge probing the interaction between potential drug compounds and membrane proteins with single molecule resolution1. It is enabling inhibition in solution perturbations of the interaction to reveal detailed kinetic information, coined dynamic inhibition in solution assay, or dISA in short . In essence, this provides label-free interaction analysis of drug-target interactions providing several advantages compared to conventional methods:
First, instead of adopting membrane proteins to a membrane-free environment, spending tremendous efforts of building a surrogate environment or trying to stabilizing them to sustain in an artificial environment, InSingulos proprietary technology allows keeping membrane proteins throughout the whole experimental workflow in the right lipid-based environment: the native cell membrane.
Second, unlike in conventional label-free assays the liposomes can remain in solution and only a tool compound has to be immobilized at the sensor surface. The interaction between the membrane protein and tool compound can be challenged with ligands of choice and unlike with other inhibition in solution assays, our technology allows to measure the interaction kinetics between the ligand and the target totally independent from the properties of the tool-compound properties. In combination with the fact that non-specific interaction between potential drug compounds and the lipid membrane surrounding or off target binding does not influence the measurements, this means that the method offer higher specificity than conventional label free methods even in complex environments.
Third, the single-molecule sensitivity, makes possible for InSingulos technology to operate using tool-compounds within a broad affinity range from sub-nanomolar to micromolar, and the same tool compound can be used throughout the whole development process from screening to end of lead optimization.
Forth, being able to measure at the single molecule level our technologies needs only small sample amounts and low target protein concentration. This enables us to overcome limitations like the tight-binding problem or ligand depletion, too.
In summary, by eliminating the need of isolation and purification of membrane proteins, one of the most common pitfalls in working with membrane proteins is abolished. Further, by delivering full kinetic interaction analysis with the highest possible sensitivity, the interaction of single molecules, our technology allows to accelerate drug development projects in an unprecedented way. Finally, being developed in close collaboration with leading drug developers our technology is made to overcome key challenges scientist in drug discovery experience when working with membrane proteins.
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1 Kaminski, Tim, Vladimir P. Zhdanov, and Fredrik Höök. ‘Single-Molecule Dynamic In-Solution Inhibition Assay: A Method for Full Kinetic Profiling of Drug Candidate Binding to GPCRs in Native Membranes’, 16 September 2021. https://doi.org/10.1101/2021.09.16.460640.