6BIX

HLA-DRB1 in complex with citrullinated LL37 peptide

Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.20 Å
  • R-Value Free: 0.212 
  • R-Value Work: 0.169 
  • R-Value Observed: 0.171 

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Ligand Structure Quality Assessment 


This is version 1.3 of the entry. See complete history. 


Literature

The interplay between citrullination and HLA-DRB1 polymorphism in shaping peptide binding hierarchies in rheumatoid arthritis.

Ting, Y.T., Petersen, J., Ramarathinam, S.H., Scally, S.W., Loh, K.L., Thomas, R., Suri, A., Baker, D.G., Purcell, A.W., Reid, H.H., Rossjohn, J.

(2018) J Biol Chem 293: 3236-3251

  • DOI: 10.1074/jbc.RA117.001013
  • Primary Citation of Related Structures:  
    6BIJ, 6BIL, 6BIN, 6BIR, 6BIV, 6BIX, 6BIY, 6BIZ

  • PubMed Abstract: 

    • The HLA-DRB1 locus is strongly associated with rheumatoid arthritis (RA) susceptibility, whereupon citrullinated self-peptides bind to HLA-DR molecules bearing the shared epitope (SE) amino acid motif. However, the differing propensity for citrullinated/non-citrullinated self-peptides to bind given HLA-DR allomorphs remains unclear ...

    The HLA-DRB1 locus is strongly associated with rheumatoid arthritis (RA) susceptibility, whereupon citrullinated self-peptides bind to HLA-DR molecules bearing the shared epitope (SE) amino acid motif. However, the differing propensity for citrullinated/non-citrullinated self-peptides to bind given HLA-DR allomorphs remains unclear. Here, we used a fluorescence polarization assay to determine a hierarchy of binding affinities of 34 self-peptides implicated in RA against three HLA-DRB1 allomorphs (HLA-DRB1*04:01/*04:04/*04:05) each possessing the SE motif. For all three HLA-DRB1 allomorphs, we observed a strong correlation between binding affinity and citrullination at P4 of the bound peptide ligand. A differing hierarchy of peptide-binding affinities across the three HLA-DRB1 allomorphs was attributable to the β-chain polymorphisms that resided outside the SE motif and were consistent with sequences of naturally presented peptide ligands. Structural determination of eight HLA-DR4-self-epitope complexes revealed strict conformational convergence of the P4-Cit and surrounding HLA β-chain residues. Polymorphic residues that form part of the P1 and P9 pockets of the HLA-DR molecules provided a structural basis for the preferential binding of the citrullinated self-peptides to the HLA-DR4 allomorphs. Collectively, we provide a molecular basis for the interplay between citrullination of self-antigens and HLA polymorphisms that shape peptide-HLA-DR4 binding affinities in RA.

    Organizational Affiliation: 

    the Institute of Infection and Immunity, Cardiff University School of Medicine, Heath Park, Cardiff CF14 4XN, Wales, United Kingdom.



Macromolecules
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Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
HLA class II histocompatibility antigen, DR alpha chainA189Homo sapiensMutation(s): 0 
Gene Names: HLA-DRA, HLA-DRA1
UniProt & NIH Common Fund Data Resources
Find proteins for P01903 (Homo sapiens)
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Go to UniProtKB:  P01903
PHAROS:  P01903
Entity Groups  
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UniProt GroupP01903
Protein Feature View
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Entity ID: 2
MoleculeChainsSequence LengthOrganismDetailsImage
HLA class II DR-beta (HLA-DR B)B200Homo sapiensMutation(s): 0 
Gene Names: HLA-DRB1
UniProt & NIH Common Fund Data Resources
Find proteins for P01911 (Homo sapiens)
Explore P01911 
Go to UniProtKB:  P01911
PHAROS:  P01911
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UniProt GroupP01911
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Entity ID: 3
MoleculeChainsSequence LengthOrganismDetailsImage
LL37_Cit91C13Homo sapiensMutation(s): 0 
Gene Names: CAMP, CAP18, FALL39, HSD26
UniProt & NIH Common Fund Data Resources
Find proteins for P49913 (Homo sapiens)
Explore P49913 
Go to UniProtKB:  P49913
PHAROS:  P49913
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UniProt GroupP49913
Protein Feature View
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  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
NAG
Query on NAG
Download Ideal Coordinates CCD File 
D [auth A],
E [auth A]		2-acetamido-2-deoxy-beta-D-glucopyranose
C8 H15 N O6
OVRNDRQMDRJTHS-FMDGEEDCSA-N		 Ligand Interaction
Modified Residues  1 Unique
IDChainsTypeFormula2D DiagramParent
CIR
Query on CIR		C L-PEPTIDE LINKINGC6 H13 N3 O3ARG
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.20 Å
  • R-Value Free: 0.212 
  • R-Value Work: 0.169 
  • R-Value Observed: 0.171 
  • Space Group: C 2 2 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 67.337α = 90
b = 183.059β = 90
c = 78.435γ = 90
Software Package:
Software NamePurpose
Aimlessdata scaling
PHENIXrefinement
PDB_EXTRACTdata extraction
XDSdata reduction
PHASERphasing

Structure Validation

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Ligand Structure Quality Assessment 


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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2018-01-17
    Type: Initial release
  • Version 1.1: 2018-01-24
    Changes: Database references, Structure summary
  • Version 1.2: 2018-03-14
    Changes: Database references
  • Version 1.3: 2020-07-29
    Type: Remediation
    Reason: Carbohydrate remediation
    Changes: Data collection, Derived calculations, Structure summary