Bis-sulfone-PEG4-DBCO

Bis-sulfone-PEG4-DBCO is a bifunctional PROTAC linker designed to connect an E3-ligase ligand and a target-binding warhead through a flexible polyethylene glycol spacer while incorporating a DBCO handle for efficient bioorthogonal conjugation. Its sulfone-containing motif can support robust, polar linkage behavior, and the PEG segment helps modulate solubility and effective reach in ternary-complex formation. The molecule is well suited for modular PROTAC assembly workflows, and the details below describe its structural features and practical reactivity considerations.

Structure: The linker contains a PEG-based flexible chain and a bis-sulfone segment, providing polar sulfone functionalities and ether-rich connectivity. A DBCO (dibenzocyclooctyne) moiety enables strain-promoted cycloaddition, with aromatic and aliphatic components contributing to overall stability and conjugation-ready geometry.

Reactivity: DBCO groups react with complementary strained or cyclooctyne-compatible partners via strain-promoted azide–alkyne cycloaddition, typically under mild aqueous or mixed-solvent conditions. For PROTAC construction, the linker is commonly used to install one conjugation handle onto a ligand and then couple the second component through the orthogonal cycloaddition step. Reactions are generally performed without copper catalysts to preserve sensitive biomolecules, using standard buffering and compatible solvent systems to maintain solubility.