Effect of Drug-to-Protein Reaction Kinetics on the Results of Thermal Proteome Profiling.

In this Letter, a two-term formalism for constructing protein solubility curves in thermal proteome profiling (TPP) is considered, which takes into account the efficiency of the drug-protein binding reaction. When the reaction is incomplete, this results in distortion of the otherwise sigmoidal shape of the curve after drug treatment, which is often observed in experiments. This distortion may be significant enough to disqualify the corresponding protein from the list of drug target candidates, thus negatively affecting the results of TPP data analysis. To further assist this analysis, we also developed the solubility curve simulation software to visualize the discussed effect. Several experimental data sets from recent TPP studies have been reprocessed, and we demonstrate in a few examples that the proposed two-term equation fits correctly the observed protein solubility curves with distorted shapes, also highlighting the previously unrecognized targets.