The 4th and 5th C-terminal domains of Factor H related protein 1

Experimental Data Snapshot

  • Resolution: 2.90 Å
  • R-Value Free: 0.269 
  • R-Value Work: 0.207 
  • R-Value Observed: 0.213 

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The Major Autoantibody Epitope on Factor H in Atypical Hemolytic Uremic Syndrome Is Structurally Different from Its Homologous Site in Factor H-related Protein 1, Supporting a Novel Model for Induction of Autoimmunity in This Disease.

Bhattacharjee, A.Reuter, S.Trojnar, E.Kolodziejczyk, R.Seeberger, H.Hyvarinen, S.Uzonyi, B.Szilagyi, A.Prohaszka, Z.Goldman, A.Jozsi, M.Jokiranta, T.S.

(2015) J Biol Chem 290: 9500-9510

  • DOI: https://doi.org/10.1074/jbc.M114.630871
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    Atypical hemolytic uremic syndrome (aHUS) is characterized by complement attack against host cells due to mutations in complement proteins or autoantibodies against complement factor H (CFH). It is unknown why nearly all patients with autoimmune aHUS lack CFHR1 (CFH-related protein-1). These patients have autoantibodies against CFH domains 19 and 20 (CFH19-20), which are nearly identical to CFHR1 domains 4 and 5 (CFHR14-5). Here, binding site mapping of autoantibodies from 17 patients using mutant CFH19-20 constructs revealed an autoantibody epitope cluster within a loop on domain 20, next to the two buried residues that are different in CFH19-20 and CFHR14-5. The crystal structure of CFHR14-5 revealed a difference in conformation of the autoantigenic loop in the C-terminal domains of CFH and CFHR1, explaining the variation in binding of autoantibodies from some aHUS patients to CFH19-20 and CFHR14-5. The autoantigenic loop on CFH seems to be generally flexible, as its conformation in previously published structures of CFH19-20 bound to the microbial protein OspE and a sialic acid glycan is somewhat altered. Cumulatively, our data suggest that association of CFHR1 deficiency with autoimmune aHUS could be due to the structural difference between CFHR1 and the autoantigenic CFH epitope, suggesting a novel explanation for CFHR1 deficiency in the pathogenesis of autoimmune aHUS.

  • Organizational Affiliation

    From the Department of Bacteriology and Immunology, Medicum, and Immunobiology Research Program Unit, University of Helsinki and Helsinki University Hospital, 00014 University of Helsinki, Finland, the Institute of Biotechnology and arnab.bhattacharjee@helsinki.fi.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Complement factor H-related protein 1
A, B
125Homo sapiensMutation(s): 0 
UniProt & NIH Common Fund Data Resources
Find proteins for Q03591 (Homo sapiens)
Explore Q03591 
Go to UniProtKB:  Q03591
PHAROS:  Q03591
GTEx:  ENSG00000244414 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ03591
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.90 Å
  • R-Value Free: 0.269 
  • R-Value Work: 0.207 
  • R-Value Observed: 0.213 
  • Space Group: P 6 2 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 143.406α = 90
b = 143.406β = 90
c = 77.784γ = 120
Software Package:
Software NamePurpose
ADSCdata collection
DNAdata collection
XDSdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2015-02-18
    Type: Initial release
  • Version 1.1: 2015-02-25
    Changes: Database references
  • Version 1.2: 2015-05-06
    Changes: Database references