Histone methylation plays a key role in establishing and maintaining stable gene expression patterns during cellular differentiation and embryonic development. Considering that a number of small molecules identified as modulators of methyltransferases by high-throughput screening were dyes or derivatives, a small focused library of dye-like compounds was prepared and the small molecules synthesized were pre-screened for potential inhibition of histone lysine methyltransferases (HKMT) using in vitro HMT assays. Two compounds, EPI-
9 and EPI-23, showed low IC50 values against nucleosomal HKMT PR-Set7. Prompted by our interest in the study of small molecule modulators of these epigenetic targets, we applied MST (Microscale Thermophoresis) to the investigation of the interaction of PRset7 with small molecule ligands EPI-9 and EPI-23. Microscale thermophoresis (MST) is a new method that enables the quantitative analysis of molecular interactions in solution. MST is the directed movement of particles in a microscopic temperature gradient: any change of the hydration
shell of biomolecules due to changes in their structure/conformation results in a relative change of movement along the temperature gradient and is used to determine binding affinities, binding kinetics and activity kinetics. Events such as the binding of small molecules to a target can be monitored by this tecnique
