1xiw
From Proteopedia
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Crystal structure of human CD3-e/d dimer in complex with a UCHT1 single-chain antibody fragment
Overview
The alpha/beta T cell receptor complex transmits signals from MHC/peptide, antigens through a set of constitutively associated signaling molecules, including CD3-epsilon/gamma and CD3-epsilon/delta. We report the crystal, structure at 1.9-A resolution of a complex between a human, CD3-epsilon/delta ectodomain heterodimer and a single-chain fragment of, the UCHT1 antibody. CD3-epsilon/delta and CD3-epsilon/gamma share a, conserved interface between the Ig-fold ectodomains, with parallel packing, of the two G strands. CD3-delta has a more electronegative surface and a, more compact Ig fold than CD3-gamma; thus, the two CD3 heterodimers have, distinctly different molecular surfaces. The UCHT1 antibody binds near an, acidic region of CD3-epsilon opposite the dimer interface, occluding this, region from direct interaction with the TCR. This immunodominant epitope, may be a uniquely accessible surface in the TCR/CD3 complex, because there, is overlap between the binding site of the UCHT1 and OKT3 antibodies., Determination of the CD3-epsilon/delta structure completes the set of, TCR/CD3 globular ectodomains and contributes information about exposed CD3, surfaces.
About this Structure
1XIW is a Protein complex structure of sequences from Homo sapiens and Mus musculus. Full crystallographic information is available from OCA.
Reference
Crystal structure of a human CD3-epsilon/delta dimer in complex with a UCHT1 single-chain antibody fragment., Arnett KL, Harrison SC, Wiley DC, Proc Natl Acad Sci U S A. 2004 Nov 16;101(46):16268-73. Epub 2004 Nov 8. PMID:15534202
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