Crystal structure of the Kelch domain in complex with 11 amino acid peptide (model of the ETGE loop)

Experimental Data Snapshot

  • Resolution: 2.75 Å
  • R-Value Free: 0.258 
  • R-Value Work: 0.181 

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This is version 1.3 of the entry. See complete history


Binding of dipeptidyl peptidase III to the oxidative stress cell sensor Kelch-like ECH-associated protein 1 is a two-step process.

Matic, S.Kekez, I.Tomin, M.Bogar, F.Supljika, F.Kazazic, S.Hanic, M.Jha, S.Brkic, H.Bourgeois, B.Madl, T.Gruber, K.Macheroux, P.Matkovic-Calogovic, D.Matovina, M.Tomic, S.

(2021) J Biomol Struct Dyn 39: 6870-6881

  • DOI: https://doi.org/10.1080/07391102.2020.1804455
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    This work is about synergy of theory and experiment in revealing mechanism of binding of dipeptidyl peptidase III (DPP III) and Kelch-like ECH-associated protein 1 (KEAP1), the main cellular sensor of oxidative stress. The NRF2 ̶ KEAP1 signaling pathway is important for cell protection, but it is also impaired in many cancer cells where NRF2 target gene expression leads to resistance to chemotherapeutic drugs. DPP III competitively binds to KEAP1 in the conditions of oxidative stress and induces release of NRF2 and its translocation into nucleus. The binding is established mainly through the ETGE motif of DPP III and the Kelch domain of KEAP1. However, although part of a flexible loop, ETGE itself is firmly attached to the DPP III surface by strong hydrogen bonds. Using combined computational and experimental study, we found that DPP III ̶ Kelch binding is a two-step process comprising the endergonic loop detachment and exergonic DPP III ̶ Kelch interaction. Substitution of arginines, which keep the ETGE motif attached, decreases the work needed for its release and increases DPP III ̶ Kelch binding affinity. Interestingly, mutations of one of these arginine residues have been reported in cBioPortal for cancer genomics, implicating its possible involvement in cancer development. Communicated by Ramaswamy H. Sarma.

  • Organizational Affiliation

    Divison of Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Zagreb, Croatia.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Kelch-like ECH-associated protein 1A [auth AAA]288Homo sapiensMutation(s): 0 
Gene Names: KEAP1INRF2KIAA0132KLHL19
UniProt & NIH Common Fund Data Resources
Find proteins for Q14145 (Homo sapiens)
Explore Q14145 
Go to UniProtKB:  Q14145
PHAROS:  Q14145
GTEx:  ENSG00000079999 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ14145
Sequence Annotations
  • Reference Sequence

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Entity ID: 2
MoleculeChains Sequence LengthOrganismDetailsImage
VAL-ILE-ASN-PRO-GLU-THR-GLY-GLU-GLN-ILE-GLNB [auth PPP]11Homo sapiensMutation(s): 0 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
NA (Subject of Investigation/LOI)
Query on NA

Download Ideal Coordinates CCD File 
Experimental Data & Validation

Experimental Data

  • Resolution: 2.75 Å
  • R-Value Free: 0.258 
  • R-Value Work: 0.181 
  • Space Group: P 31 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 75.296α = 90
b = 75.296β = 90
c = 127.539γ = 120
Software Package:
Software NamePurpose
CrysalisProdata reduction
Aimlessdata scaling

Structure Validation

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Entry History & Funding Information

Deposition Data

Funding OrganizationLocationGrant Number
Croatian Science FoundationCroatia--

Revision History  (Full details and data files)

  • Version 1.0: 2020-09-16
    Type: Initial release
  • Version 1.1: 2020-09-23
    Changes: Database references
  • Version 1.2: 2021-10-27
    Changes: Data collection, Database references
  • Version 1.3: 2024-01-24
    Changes: Data collection, Derived calculations, Refinement description