Discussion

Identifying protein partners of a small bioactive molecule is of great interest in many aspects of life sciences and specifically in the drug discovery and development process cycle. It is a support to (i) decipher the mechanism of action after for example a “High Content” screening, (ii) study “off-target” effects, (iii) adjust therapeutic indications and clinical regimens of a drug and (iv) consider drug repositioning.
ULTImate YChemH is a chemical biology tool for direct targets identification. This method is based on the well-established yeast two-hybrid (Y2H) technology. The small molecule of interest is used as a bait to screen highly complex protein domain libraries. The small molecule - protein interactions are detected thanks to the reconstitution of an active transcription factor from DNA Binding Domain (DBD) and Activation Domain (AD) moieties. When an interaction takes place, the bait derivative bridges the gap between the DBD and the AD. This enables the expression of the reporter gene and subsequent yeast growth on a selective medium. Positive clones are then analyzed by sequencing to identify the protein partners.
One example with a hit coming from a “black box” screen highlights how this technology can be easily applied for target identification.