Aptamer-linked JQ1 conjugates offer a cell-free way to compare E2/E3 ubiquitination of BRD4
- JQ1 was attached by click chemistry to a DNA aptamer that binds His tags, so any His-tagged E3 can be recruited to BRD4 without custom ligands.
- In a reconstituted system, the conjugates drove BRD4 polyubiquitination with VHL complex, with a drop at high dose consistent with a hook effect.
- Different E3 and E2 combinations gave distinct ubiquitin patterns; lysine-free ubiquitin and conjugate length helped separate chain growth from multi-site modification.
💡 Points Based on the abstract
As a tool compound this is attractive: swapping E3 ligands for a His-tag handle makes E3 comparisons ligand-free and clean. But a cell-free readout with a big DNA linker says little about real degraders, where ternary-complex geometry, permeability and linker length drive degradation. Next step: benchmark against a matched JQ1–VHL PROTAC (e.g., MZ1) in the same assay to see whether ubiquitination patterns track cellular DC50.