9HWQ | pdb_00009hwq

Crystal structure of the Keap1 Kelch domain in complex with the XChem fragment Z19735904 at 1.14 Angstrom resolution.


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.14 Å
  • R-Value Free: 
    0.164 (Depositor), 0.164 (DCC) 
  • R-Value Work: 
    0.145 (Depositor), 0.145 (DCC) 
  • R-Value Observed: 
    0.146 (Depositor) 

Starting Model: experimental
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Ligand Structure Quality Assessment 


This is version 1.1 of the entry. See complete history


Literature

Fragment-Based Drug Discovery of Novel High-affinity, Selective, and Anti-inflammatory Inhibitors of the Keap1-Nrf2 Protein-Protein Interaction.

Lin, C.Narayanan, D.Barreca, M.Poulsen, C.da Costa, L.S.Chen, X.Wichman, K.G.Charley, C.A.Lindsay, J.L.Dezfouli, M.Vlissari, D.Mortensen, T.S.Chan, C.B.Wang, J.Richardson, W.Manning, C.E.Chen, Z.Zang, J.Kack, H.Gajhede, M.Bullock, A.N.Blake, D.J.Olagnier, D.Bach, A.

(2025) Angew Chem Int Ed Engl 64

  • DOI: https://doi.org/10.1002/anie.202508121
  • Primary Citation of Related Structures:  
    9HWQ, 9HWR, 9HWS, 9HWT, 9HWU, 9HWV, 9HWW, 9HWX

  • PubMed Abstract: 

    Activating the cytoprotective response of nuclear factor erythroid 2-related factor 2 (Nrf2) can reduce oxidative stress and inflammation. A promising strategy is to inhibit the protein-protein interaction between Kelch-like ECH-associated protein 1 (Keap1) and Nrf2 using noncovalent compounds that target the Keap1 Kelch domain. These compounds may be more specific than covalent Keap1-reacting Nrf2 activators. However, the development of drug-like noncovalent Keap1-Nrf2 inhibitors faces challenges due to the size and polarity of the Kelch binding pocket. Here, we present a new series of noncovalent Keap1-Nrf2 inhibitors developed from a weak fragment hit identified by crystallographic screening. A two-step growing strategy and optimization guided by several X-ray cocrystal structures led to compounds with low nanomolar affinities and complete selectivity for Keap1 in a panel of homologous Kelch domains. In cells, compounds 24 and 28 potently activated the expression of Nrf2-controlled genes and showed anti-inflammatory effects by downregulating NLRP3 inflammasome and STING signalling activation. RNA sequencing revealed activation of cytoprotective pathways and a different profile from typical covalent Nrf2 activators. This work highlights the potential of fragment-based drug discovery for challenging targets like Keap1 and introduces novel Keap1-Nrf2 inhibitors as chemical probes and drug leads.


  • Organizational Affiliation
    • Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, 2100, Denmark.

Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Kelch-like ECH-associated protein 1304Mus musculusMutation(s): 0 
Gene Names: Keap1Inrf2Kiaa0132
UniProt
Find proteins for Q9Z2X8 (Mus musculus)
Explore Q9Z2X8 
Go to UniProtKB:  Q9Z2X8
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ9Z2X8
Sequence Annotations
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  • Reference Sequence
Small Molecules
Ligands 3 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
B0A (Subject of Investigation/LOI)
Query on B0A

Download Ideal Coordinates CCD File 
B [auth A]~{N}-cyclohexyl-2-phenoxy-ethanamide
C14 H19 N O2
CQWWLWGATIFQLU-UHFFFAOYSA-N
SO4
Query on SO4

Download Ideal Coordinates CCD File 
C [auth A],
D [auth A],
E [auth A],
F [auth A],
G [auth A]
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
DMS
Query on DMS

Download Ideal Coordinates CCD File 
H [auth A]
I [auth A]
J [auth A]
K [auth A]
L [auth A]
H [auth A],
I [auth A],
J [auth A],
K [auth A],
L [auth A],
M [auth A],
N [auth A],
O [auth A],
P [auth A]
DIMETHYL SULFOXIDE
C2 H6 O S
IAZDPXIOMUYVGZ-UHFFFAOYSA-N
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.14 Å
  • R-Value Free:  0.164 (Depositor), 0.164 (DCC) 
  • R-Value Work:  0.145 (Depositor), 0.145 (DCC) 
  • R-Value Observed: 0.146 (Depositor) 
Space Group: P 61
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 103.146α = 90
b = 103.146β = 90
c = 55.225γ = 120
Software Package:
Software NamePurpose
XDSdata reduction
Aimlessdata scaling
PHASERphasing
PHENIXrefinement
PDB_EXTRACTdata extraction

Structure Validation

View Full Validation Report



Ligand Structure Quality Assessment 


Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
LundbeckfondenDenmarkR366-2021-270

Revision History  (Full details and data files)

  • Version 1.0: 2025-09-03
    Type: Initial release
  • Version 1.1: 2025-10-01
    Changes: Database references