We have developed a proprietary cell lysate‐based chemical protein denaturation technology to confirm protein target engagement. This is accomplished by assessing binding-induced stabilisation in a simple mix-and-read, scalable, cost‐effective assay.

Determining ligand target engagement is an essential process for hit discovery and lead profiling, where simple and rapid approaches are highly valuable tools in the drug discovery toolbox. CPSA is unique in that it only requires mix-and-read steps within a single assay plate, giving a streamlined, cost‐effective workflow without transfer steps. The use of cell lysates avoids potential difficulties with the purification of protein targets.

CPSA is adept at handling diverse needs, from rapid evaluation of a few lead compounds to 1536-well screening of large-scale libraries. As it does not rely on target activity, CPSA has the potential to identify novel series that bind outside of the active site and move into novel chemical space.

What is CPSA, and how does it work?

Our patented assay applies to a range of cellular protein targets and can be configured using a range of protein detection technologies, depending on the throughput required for analysis.

CPSA is a lysate‐based, single‐well, mix-and-read assay without plate transfers to measure target engagement. Chemical denaturants are utilised to unfold proteins, and target engagement is confirmed by measuring the increased stability imparted to the target by your chosen ligand. It is highly amenable to plate-based compound screening and can generate high‐quality data in both dose-response and single-point formats. As a label-free method requiring no modification of target or ligand, the true pharmacology of the molecule is retained, giving CPSA broad scope and enhanced physiologic relevance. Cell lysate fits well with large‐scale applications where confounding cellular permeability effects are not desirable at early hit ID while avoiding issues with large‐scale protein purification.

The simplicity of the workflow and reagents reduces assay variability and produces consistent data. CPSA is broadly applicable to a wide range of cellular targets. Data generated using CPSA is comparable to that generated using established alternative techniques, which demonstrates the application of this technique to compound screening and hit-finding activities.

How does CPSA compare to standard protein stability assays?

Current industry standard protein stability assay follows a process of high-temperature incubations, lysis steps, and plate-to-plate transfers, which can be time-consuming and yield inconsistencies:

CPSA presents a simplified workflow suitable for HTS with relatively few steps. The use of lysate removes the need to generate isolated protein, and it does not require high-temperature incubations.