Discovery of hit compounds for methyl-lysine reader proteins from a target class DNA-encoded library

Discovery of a 53BP1 Small Molecule Antagonist Using a Focused DNA-Encoded Library Screen

“…In our efforts to discover novel antagonists for the 53BP1 TTD, we utilized a previously reported in-house DEL biased to interact with Kme reader domains. , This library, UNCDEL003, is part of our extended efforts to establish a target class platform to identify chemical probes targeting Kme reader protein domains using DELs. − UNCDEL003 has been used extensively for screening various Kme reader domains, leading to recently reported hit compounds for the 53BP1 TTD as well as the PHD domain of plant homeodomain finger protein 8 (PHF8/KDM7B) . Based on our prior successes, we aimed to use a similar strategy to identify 53BP1 TTD hits with improved potency.…”

“…This compound was favored across the graphical visualization of individual synthons and quantitative selection frequencies. For initial validation, UNC8531 was synthesized off-DNA (Scheme ) and tested in an established TR-FRET assay to evaluate competitive displacement of a dimethyl lysine-containing p53 peptide from the 53BP1 TTD protein . In this assay, UNC8531 exhibited an IC 50 of 0.47 ± 0.09 μM (Figure B).…”

“…For initial validation, UNC8531 was synthesized off-DNA (Scheme 1) and tested in an established TR-FRET assay to evaluate competitive displacement of a dimethyl lysine-containing p53 peptide from the 53BP1 TTD protein. 34 In this assay, UNC8531 exhibited an IC 50 of 0.47 ± 0.09 μM (Figure 1B). Compound binding was further validated through both ITC and SPR experiments, revealing K d values of 0.85 ± 0.17 and 0.79 ± 0.52 μM, respectively (Figures 1C,D and S2).…”

“…Here, we utilized a focused DNA-encoded library (DEL), UNCDEL003, to screen and identify hit compounds for the 53BP1 TTD. 34,35 We successfully identified and characterized a novel, potent hit compound, UNC8531 (1), which has an IC 50 of 0.47 ± 0.09 μM in a time-resolved fluorescence resonance energy transfer (TR-FRET) displacement assay. Isothermal titration calorimetry (ITC) and surface plasmon resonance (SPR) were used as orthogonal assays to reveal K d values of 0.85 ± 0.17 and 0.79 ± 0.52 μM, respectively.…”

“…36−41 UNCDEL003 has been used extensively for screening various Kme reader domains, leading to recently reported hit compounds for the 53BP1 TTD as well as the PHD domain of plant homeodomain finger protein 8 (PHF8/ KDM7B). 34 Based on our prior successes, we aimed to use a similar strategy to identify 53BP1 TTD hits with improved potency. To do this, we used a traditional DEL screening workflow (Figure S1).…”