Extended Data Fig. 4 ∣. Ternary complex formation of dipeptide ligands with CRBN and BRD4.

(a) Schematic showing the domains of CRBN, including the CULT domain with key residues for immunomodulatory drug binding highlighted, and AlphaScreen design. (b–c) AlphaScreen experiments performed with the indicated degrader compounds. The relative area under the curve reflected the cellular degradation trends, with several of the dipeptide degraders resulting in a signal greater than or comparable to dBET6. Interestingly, the inactive degraderJQ1-cQ promotes ternary complex formation equivalent to the active JQ1-GcQ, indicating that the N–1 amino acid residue positions the ternary complex in a more productive conformation. Data shown in (b) and (c) are each performed on a single 384-well plate; dBET6 was assayed on each plate as an internal control. Each condition was measured in triplicate. (d) Schematic of NanoBRET assay. (e) NanoBRET measurement of ternary complex formation induced by the indicated members of the degrader library as determined by acceptor:donor signal ratio, with background signal from no-ligand control for each degrader subtracted. Each condition was assayed in triplicate. Error bars represent mean ± SEM.