Amino-PEG3-propionic acid

This amino-PEG3-propionic acid linker is designed to serve as a flexible, hydrophilic spacer in targeted protein degradation constructs, supporting efficient conjugation between a ligand and an E3-recruiting module. Its PEG-based architecture helps tune solubility and spatial presentation, which can influence ternary complex formation and degradation performance. The detailed Structure and Reactivity parameters are provided below for researchers planning PROTAC synthesis and linker incorporation.

Structure: The linker contains a PEG-derived polyether segment that provides conformational flexibility and enhanced hydrophilicity, coupled to an amino functionality and a carboxylic acid for orthogonal chemical handling. It features stable C–O ether linkages alongside amide/carboxyl-reactive groups suitable for bioconjugation.

Reactivity: The amino group is typically used for amide bond formation or for coupling to activated carboxyl groups via standard peptide-coupling chemistries. The terminal carboxylic acid can be converted to common activated intermediates (for example, acid chlorides, activated esters, or coupling reagents) for nucleophilic substitution by amines. Mild base/aqueous–organic solvent systems are commonly employed to preserve sensitive ligands and maintain linker integrity during PROTAC assembly.