TCO-PEG6-acid

TCO-PEG6-acid is a polyethylene glycol-based PROTAC linker designed to connect targeting and recruiting modules while providing aqueous compatibility and conformational flexibility. Its acid functionality enables robust coupling to amine-bearing or activated partners, supporting modular PROTAC assembly. The linker’s bioorthogonal reactive handle supports efficient conjugation strategies commonly used in targeted protein degradation workflows, and the subsequent sections describe its structural traits and practical reactivity considerations in detail below.

Structure: The linker comprises a PEG chain terminating in a carboxylic acid, providing a hydrophilic, flexible scaffold. It contains ether linkages within the PEG segment and a terminal carboxyl group capable of forming amide or ester derivatives. The overall structure supports solubility and spacer behavior in conjugates.

Reactivity: The carboxylic acid can be converted to activated intermediates for amide bond formation, typically using coupling reagents compatible with peptide/bioconjugation chemistry. For PROTAC construction, coupling is commonly performed under mild base conditions in polar aprotic solvents, followed by purification to remove excess reagents. The TCO-related functionality is generally employed in bioorthogonal conjugation schemes that proceed via strain-promoted cycloaddition, enabling efficient attachment without requiring metal catalysts.