1adq
CRYSTAL STRUCTURE OF A HUMAN IGM RHEUMATOID FACTOR FAB IN COMPLEX WITH ITS AUTOANTIGEN IGG FC
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OverviewOverview
Rheumatoid factors are the characteristic autoantibodies of rheumatoid, arthritis, which bind to the Fc regions of IgG molecules. Here we report, the crystal structure of the Fab fragment of a patient-derived IgM, rheumatoid factor (RF-AN) complexed with human IgG4 Fc, at 3.2 A, resolution. This is the first structure of an autoantibody-autoantigen, complex. The epitope recognised in IgG Fc includes the C gamma 2/C gamma 3, cleft region, and overlaps the binding sites of bacterial Fc-binding, proteins. The antibody residues involved in autorecognition are all, located at the edge of the conventional combining site surface, leaving, much of the latter available, potentially, for recognition of a different, antigen. Since an important contact residue is somatic mutation, the, structure implicates antigen-driven selection, following somatic mutation, of germline genes, in the production of pathogenic rheumatoid factors.
About this StructureAbout this Structure
1ADQ is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.
ReferenceReference
Structure of human IgM rheumatoid factor Fab bound to its autoantigen IgG Fc reveals a novel topology of antibody-antigen interaction., Corper AL, Sohi MK, Bonagura VR, Steinitz M, Jefferis R, Feinstein A, Beale D, Taussig MJ, Sutton BJ, Nat Struct Biol. 1997 May;4(5):374-81. PMID:9145108
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