Recombinant His-tagged DDB1(M1-H1140)/CRBN(M1-L442) Complex Cereblon, E3 Ligase

Hi5 insect cells were co-transfected with His_Flag_Tev_CRBN(M1-L442) and DDB1(M1-H1140). DDB1 acts as a stabilizing binding partner that mediates solubility of CRBN during expression and purification. The formation of the heterodimeric DDB1/CRBN complex was confirmed by structural analysis using X-ray crystallography. The His_Flag_Tag remains in the final product and does not interfere with crystallization or interaction of the protein with a Phenyl-Dihydrouracile (PDHU) reference compound.

Protein Construct: DDB1(M1-H1140)/His-Flag-Tev-CRBN(M1-L442)
Source: Human
Expression Host: Trichoplusia ni (Hi5)
Molecular weight: 127 kDa (DDB1); 51 kDa(CRBN)
pI: 5.57 (DDB1); 5.14 (CRBN)
Extinction Coefficient: 126966 M^-1cm^-1 (DDB1); 71850 M^-1cm^-1 (CRBN)
Concentration: 19.8 mg/mL
Storage Buffer: 50 mM HEPES pH 7.4, 200 mM NaCl, 0.5 mM TCEP
Tag: His_Flag_Tev

Amino acid sequence DDB1:

Amino acid sequence His_Flag_Tev_CRBN:

QC Data: Datasheet
Purity SDS: >95 %
Hydrodynamic Radius (nm): 6.33
Polydispersity Index (PDI): 0.21
T_on (°C): 51.2
T_{m, 1} (°C): 55.0
T_{m, 2} (°C): 62.9

Structure and function

Cereblon (CRBN) functions as the substrate receptor of the Cullin 4–RING E3 ubiquitin ligase complex by coupling target recognition to ubiquitin transfer. CRBN is bound by the DNA damage-binding protein 1 (DDB1), which serves as an adaptor protein connecting the native CRBN to the rest of the cullin-4 E3 ubiquitin ligase complex. Through its C-terminal thalidomide-binding domain, CRBN directly engages its substrates, bringing them and ubiquitin-loaded E2 into close proximity and positioning the target for polyubiquitination.

Its native targets include many important endogenous substrates, such as adenosine monophosphate-activated protein kinase subunit α1, amyloid precursor protein or glutamine synthetase.

CRBN as important drug target

CRBN and its associated E3 ubiquitin ligase are central to targeted protein degradation strategies with significant therapeutic potential. Immunomodulatory drugs such as thalidomide, lenalidomide, and pomalidomide act as molecular glues that enable CRBN to recruit new substrates (neosubstrates), leading to their ubiquitination and degradation, which has diverse anti-cancer and immunmodulatory effects. Moreover, CRBN-binding ligands have been adapted for the development of PROTACs that induce the degradation of specific clinically relevant targets, underscoring the importance of CRBN in modern drug discovery.