Thalidomide-O-PEG4-amine hydrochloride is a synthesized E3 ligase ligand-linker conjugate that incorporates the Thalidomide based cereblon ligand and a linker used in PROTAC technology[1].
PROTACs contain two different ligands connected by a linker; one is a ligand for an E3 ubiquitin ligase and the other is for the target protein. PROTACs exploit the intracellular ubiquitin-proteasome system to selectively degrade target proteins[1].
[1]. Zhang NN, et al. A Thermostable mRNA Vaccine against COVID-19. Cell. 2020;182(5):1271-1283.e16.