30HE | pdb_000030he

Crystal structure of mouse Keap1 Kelch domain with a small molecule inhibitor

• PDB DOI: https://doi.org/10.2210/pdb30HE/pdb

• Classification: TRANSCRIPTION
• Organism(s): Mus musculus
• Expression System: Escherichia coli
• Mutation(s): No 


• Deposited: 2026-04-24 Released: 2026-09-16 
• Deposition Author(s): Concha, N.
• Funding Organization(s): Not funded

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 1.40 Å
• R-Value Free: 
  0.148 (Depositor), 0.157 (DCC) 
• R-Value Work: 
  0.120 (Depositor), 0.136 (DCC) 
• R-Value Observed: 
  0.121 (Depositor) 

Starting Model: experimental

Literature

The Discovery of GSK3227634: A Potent Inhaled Inhibitor of the KEAP1/NRF2 Protein-Protein Interaction for the Treatment of Chronic Obstructive Pulmonary Disease.

Callahan, J.F., Davies, T.G., Bantscheff, M., Bedard, S., Boehm, J., Booth-Genthe, C., Concha, N., Copley, R., Davis, A., Davis, R., Eberhard, D., Foley, J., Flamberg, P., Goodwin, N.C., Heightman, T.D., Katchur, S.R., Kerns, J.K., Kmett, C., Kotzer, C.J., Landis, P., Li, T., Meinhold, D., Mulbaier, M., Nie, H., Osborn, R.R., Peakman, T.M., Peck, B., Podolin, P.L., Sweitzer, T., Yan, H., Ward, P., Werner, T., Wolfe Iii, L.A., Woolford, A.J., Wu, Z., Sanchez, Y., Rumsey, W.L.

(2026) J Med Chem 69: 20859-20876

• PubMed: 42720473 
• DOI: https://doi.org/10.1021/acs.jmedchem.6c01820
• Primary Citation Related Structures: 
  30HE


• PubMed Abstract: 
  

  KEAP1 is the key regulator of the NRF2-mediated cytoprotective response and a target for pathologies involving oxidative stress. Compounds that covalently modify KEAP1 to activate NRF2 are clinically validated; however, their chemical reactivity may drive increased off-target activity. A more selective approach involves inhibition of the KEAP1-NRF2 protein-protein interaction as exemplified by our previous bis-aryl lead KI-696 (4). We now describe the lead optimization of the bis-aryl series that focused on increasing the population of the bioactive conformation of the free ligand to drive potency while optimizing overall physicochemical properties. This resulted in the discovery of GSK3227634 (5), an ultrahigh-affinity noncovalent inhibitor of KEAP1-NRF2 (surface plasmon resonance pKd = 10.9) and the first NRF2 activator to demonstrate target engagement and efficacy in preclinical models of oxidative stress via direct delivery to the lung. Compound 5 therefore represents a novel potential agent to treat lung diseases involving oxidative stress, such as chronic obstructive pulmonary disease.

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Organizational Affiliation: 
• GSK , 1250 South Collegeville Road, Collegeville, Pennsylvania19426, United States.
Astex Pharmaceuticals , 436 Cambridge Science Park, CambridgeCB4 0QA, U.K.
Cellzome GmbH , a GSK Company, Heidelberg69117, Germany.
GSK, Gunnels Wood Road, StevenageSG1 2NY, Hertfordshire, U.K.

Biological Assembly 1  

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Monomer - A1 

Biological assembly 1 assigned by authors and generated by PISA (software)

Macromolecule Content 

• Total Structure Weight: 34.12 kDa 
• Atom Count: 2,510 
• Modeled Residue Count: 289 
• Deposited Residue Count: 304 
• Unique protein chains: 1

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Kelch-like ECH-associated protein 1	A	304	Mus musculus	Mutation(s): 0  Gene Names: Keap1, Inrf2, Kiaa0132
UniProt
Find proteins for Q9Z2X8 (Mus musculus) Explore Q9Z2X8  Go to UniProtKB:  Q9Z2X8

Small Molecules

Ligands 2 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
A1J6G (Subject of Investigation/LOI)	B [auth A]	(3S)-3-[3-[[(4R)-4-ethyl-1,1-bis(oxidanylidene)-3,4-dihydropyrido[2,3-b][1,4,5]oxathiazepin-2-yl]methyl]-4-methyl-phenyl]-3-(1-ethyl-4-methyl-benzotriazol-5-yl)propanoic acid C29 H33 N5 O5 S FSVDYFNASNQHCE-VWNXMTODSA-N
SO4	C [auth A], D [auth A]	SULFATE ION O4 S QAOWNCQODCNURD-UHFFFAOYSA-L

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 1.40 Å
• R-Value Free:  0.148 (Depositor), 0.157 (DCC) 
• R-Value Work:  0.120 (Depositor), 0.136 (DCC) 
• R-Value Observed: 0.121 (Depositor) 

Space Group: P 6₁

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 102.935	α = 90
b = 102.935	β = 90
c = 55.55	γ = 120

Software Package:

Software Name	Purpose
PHENIX	refinement
PDB_EXTRACT	data extraction
HKL-2000	data reduction
SCALEPACK	data scaling
PHENIX	phasing

Structure Validation

Entry History 

& Funding Information

Deposition Data

• Released Date: 2026-09-16 
Deposition Author(s): Concha, N.

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Funding Organization	Location	Grant Number
Not funded		--

Revision History  

• Version 1.0: 2026-09-16
  Type: Initial release
  
• Version 1.1: 2026-09-23
  Changes: Database references