Structure of PAXX

Experimental Data Snapshot

  • Resolution: 3.45 Å
  • R-Value Free: 0.268 
  • R-Value Work: 0.235 
  • R-Value Observed: 0.238 

Starting Model: experimental
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wwPDB Validation   3D Report Full Report

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DNA repair. PAXX, a paralog of XRCC4 and XLF, interacts with Ku to promote DNA double-strand break repair.

Ochi, T.Blackford, A.N.Coates, J.Jhujh, S.Mehmood, S.Tamura, N.Travers, J.Wu, Q.Draviam, V.M.Robinson, C.V.Blundell, T.L.Jackson, S.P.

(2015) Science 347: 185-188

  • DOI: https://doi.org/10.1126/science.1261971
  • Primary Citation of Related Structures:  
    3WTD, 3WTF

  • PubMed Abstract: 

    XRCC4 and XLF are two structurally related proteins that function in DNA double-strand break (DSB) repair. Here, we identify human PAXX (PAralog of XRCC4 and XLF, also called C9orf142) as a new XRCC4 superfamily member and show that its crystal structure resembles that of XRCC4. PAXX interacts directly with the DSB-repair protein Ku and is recruited to DNA-damage sites in cells. Using RNA interference and CRISPR-Cas9 to generate PAXX(-/-) cells, we demonstrate that PAXX functions with XRCC4 and XLF to mediate DSB repair and cell survival in response to DSB-inducing agents. Finally, we reveal that PAXX promotes Ku-dependent DNA ligation in vitro and assembly of core nonhomologous end-joining (NHEJ) factors on damaged chromatin in cells. These findings identify PAXX as a new component of the NHEJ machinery.

  • Organizational Affiliation

    Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, UK.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Uncharacterized protein C9orf142
A, B
206Homo sapiensMutation(s): 0 
Gene Names: C9orf142
UniProt & NIH Common Fund Data Resources
Find proteins for Q9BUH6 (Homo sapiens)
Explore Q9BUH6 
Go to UniProtKB:  Q9BUH6
GTEx:  ENSG00000148362 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ9BUH6
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 3.45 Å
  • R-Value Free: 0.268 
  • R-Value Work: 0.235 
  • R-Value Observed: 0.238 
  • Space Group: P 65 2 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 89.576α = 90
b = 89.576β = 90
c = 151.404γ = 120
Software Package:
Software NamePurpose
GDAdata collection
XDSdata reduction
Aimlessdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2015-01-21
    Type: Initial release
  • Version 1.1: 2019-12-18
    Changes: Database references
  • Version 1.2: 2023-11-08
    Changes: Data collection, Database references, Refinement description