5NLB

Crystal structure of human CUL3 N-terminal domain bound to KEAP1 BTB and 3-box

Summary for 5NLB

• Entry DOI: 10.2210/pdb5nlb/pdb
• Descriptor: Kelch-like ECH-associated protein 1, Cullin-3 (2 entities in total)
• Functional Keywords: e3 ubiquitin ligase, ligase
• Biological source: Homo sapiens (Human); More
• Total number of polymer chains: 2
• Total formula weight: 58895.46

Authors

Adamson, R.,Krojer, T.,Pinkas, D.M.,Bartual, S.G.,Burgess-Brown, N.A.,Borkowska, O.,Chalk, R.,Newman, J.A.,Kopec, J.,Dixon-Clarke, S.E.,Mathea, S.,Sethi, R.,Velupillai, S.,Mackinnon, S.,von Delft, F.,Arrowsmith, C.H.,Edwards, A.M.,Bountra, C.,Bullock, A. (deposition date: 2017-04-04, release date: 2017-04-19, Last modification date: 2024-01-17)

Primary citation

Adamson, R.J.,Payne, N.C.,Bartual, S.G.,Mazitschek, R.,Bullock, A.N.
Structural and biochemical characterization establishes a detailed understanding of KEAP1-CUL3 complex assembly.
Free Radic Biol Med, 204:215-225, 2023

PubMed Abstract: KEAP1 promotes the ubiquitin-dependent degradation of NRF2 by assembling into a CUL3-dependent ubiquitin ligase complex. Oxidative and electrophilic stress inhibit KEAP1 allowing NRF2 to accumulate for the transactivation of stress response genes. To date there are no structures of the KEAP1-CUL3 interaction nor binding data to show the contributions of different domains to their binding affinity. We determined a crystal structure of the BTB and 3-box domains of human KEAP1 in complex with the CUL3 N-terminal domain that showed a heterotetrameric assembly with 2:2 stoichiometry. To support the structural data, we developed a versatile TR-FRET-based assay system to profile the binding of BTB-domain-containing proteins to CUL3 and determine the contribution of distinct protein features, revealing the importance of the CUL3 N-terminal extension for high affinity binding. We further provide direct evidence that the investigational drug CDDO does not disrupt the KEAP1-CUL3 interaction, even at high concentrations, but reduces the affinity of KEAP1-CUL3 binding. The TR-FRET-based assay system offers a generalizable platform for profiling this protein class and may form a suitable screening platform for ligands that disrupt these interactions by targeting the BTB or 3-box domains to block E3 ligase function.

PubMed: 37156295
DOI: 10.1016/j.freeradbiomed.2023.04.021

Experimental method

X-RAY DIFFRACTION (3.45 Å)