5MUB

ACC1 Fab fragment in complex with citrullinated C1 epitope of CII (CG05)

  • Classification: IMMUNE SYSTEM

  • Deposited: 2017-01-13 Released: 2017-07-19 
  • Deposition Author(s): Dobritzsch, D., Holmdahl, R., Ge, C.
  • Funding Organization(s): Swedish Foundation for Strategic Research; Knut and Alice Wallenberg Foundation; Swedish Research Council; European Union 

Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.1 Å
  • R-Value Free: 0.264 
  • R-Value Work: 0.231 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

Anti-citrullinated protein antibodies cause arthritis by cross-reactivity to joint cartilage.

Ge, C.Tong, D.Liang, B.Lonnblom, E.Schneider, N.Hagert, C.Viljanen, J.Ayoglu, B.Stawikowska, R.Nilsson, P.Fields, G.B.Skogh, T.Kastbom, A.Kihlberg, J.Burkhardt, H.Dobritzsch, D.Holmdahl, R.

(2017) JCI Insight 2: --

  • DOI: 10.1172/jci.insight.93688
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Today, it is known that autoimmune diseases start a long time before clinical symptoms appear. Anti-citrullinated protein antibodies (ACPAs) appear many years before the clinical onset of rheumatoid arthritis (RA). However, it is still unclear if and ...

    Today, it is known that autoimmune diseases start a long time before clinical symptoms appear. Anti-citrullinated protein antibodies (ACPAs) appear many years before the clinical onset of rheumatoid arthritis (RA). However, it is still unclear if and how ACPAs are arthritogenic. To better understand the molecular basis of pathogenicity of ACPAs, we investigated autoantibodies reactive against the C1 epitope of collagen type II (CII) and its citrullinated variants. We found that these antibodies are commonly occurring in RA. A mAb (ACC1) against citrullinated C1 was found to cross-react with several noncitrullinated epitopes on native CII, causing proteoglycan depletion of cartilage and severe arthritis in mice. Structural studies by X-ray crystallography showed that such recognition is governed by a shared structural motif "RG-TG" within all the epitopes, including electrostatic potential-controlled citrulline specificity. Overall, we have demonstrated a molecular mechanism that explains how ACPAs trigger arthritis.


    Organizational Affiliation

    Section for Medical Inflammation Research, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
ACC1 Fab fragment heavy chain
A, C, I, L, O, U
218N/AMutation(s): 0 
Protein Feature View is not available: No corresponding UniProt sequence found.
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
ACC1 Fab fragment light chain
B, D, G, J, M, P, S, V
218N/AMutation(s): 0 
Protein Feature View is not available: No corresponding UniProt sequence found.
Entity ID: 3
MoleculeChainsSequence LengthOrganismDetails
triple-helical peptide containing the citrullinated C1 epitope of collagen type II,Collagen alpha-1(II) chain,triple-helical peptide containing the citrullinated C1 epitope of collagen type II
X, E, H, K, N, Q, T, W
33N/AMutation(s): 0 
Protein Feature View is not available: No corresponding UniProt sequence found.
Entity ID: 4
MoleculeChainsSequence LengthOrganismDetails
ACC1 Fab fragment heavy chain
F, R
220N/AMutation(s): 0 
Protein Feature View is not available: No corresponding UniProt sequence found.
Small Molecules
Modified Residues  2 Unique
IDChainsTypeFormula2D DiagramParent
HYP
Query on HYP
E, H, K, N, Q, T, W, X
L-PEPTIDE LINKINGC5 H9 N O3PRO
CIR
Query on CIR
E, H, K, N, Q, T, W, X
L-PEPTIDE LINKINGC6 H13 N3 O3ARG
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.1 Å
  • R-Value Free: 0.264 
  • R-Value Work: 0.231 
  • Space Group: P 21 21 21
Unit Cell:
Length (Å)Angle (°)
a = 148.286α = 90.00
b = 155.099β = 90.00
c = 156.266γ = 90.00
Software Package:
Software NamePurpose
REFMACrefinement
PHASERphasing
Aimlessdata scaling
XDSdata reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
Swedish Foundation for Strategic ResearchSwedenRBa08-0047
Swedish Foundation for Strategic ResearchSwedenRB13-015
Knut and Alice Wallenberg FoundationSwedenKAW 2010.0148
Swedish Research CouncilSwedenK2011-52X-07931-25-5, 2015-02662, K2009-75SX-21029-01-3, K2012-75SX-22072-01-3
European UnionIMI 115142

Revision History 

  • Version 1.0: 2017-07-19
    Type: Initial release
  • Version 1.1: 2017-09-13
    Type: Author supporting evidence