2pyf

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Crystal Structures of High Affinity Human T-Cell Receptors Bound to pMHC RevealNative Diagonal Binding Geometry Unbound TCR Clone 5-1

Structural highlights

2pyf is a 2 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:X-ray diffraction, Resolution 2.2Å
Ligands:PG4, PGE, SO4
Resources:FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Disease

TRAC_HUMAN TCR-alpha-beta-positive T-cell deficiency. The disease is caused by variants affecting the gene represented in this entry.

Function

TRAC_HUMAN Constant region of T cell receptor (TR) alpha chain (PubMed:24600447). Alpha-beta T cell receptors are antigen specific receptors which are essential to the immune response and are present on the cell surface of T lymphocytes. Recognize peptide-major histocompatibility (MH) (pMH) complexes that are displayed by antigen presenting cells (APC), a prerequisite for efficient T cell adaptive immunity against pathogens (PubMed:25493333). Binding of alpha-beta TR to pMH complex initiates TR-CD3 clustering on the cell surface and intracellular activation of LCK that phosphorylates the ITAM motifs of CD3G, CD3D, CD3E and CD247 enabling the recruitment of ZAP70. In turn, ZAP70 phosphorylates LAT, which recruits numerous signaling molecules to form the LAT signalosome. The LAT signalosome propagates signal branching to three major signaling pathways, the calcium, the mitogen-activated protein kinase (MAPK) kinase and the nuclear factor NF-kappa-B (NF-kB) pathways, leading to the mobilization of transcription factors that are critical for gene expression and essential for T cell growth and differentiation (PubMed:23524462). The T cell repertoire is generated in the thymus, by V-(D)-J rearrangement. This repertoire is then shaped by intrathymic selection events to generate a peripheral T cell pool of self-MH restricted, non-autoaggressive T cells. Post-thymic interaction of alpha-beta TR with the pMH complexes shapes TR structural and functional avidity (PubMed:15040585).[1] [2] [3] [4]

Evolutionary Conservation

Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.

Publication Abstract from PubMed

Naturally selected T-cell receptors (TCRs) are characterised by low binding affinities, typically in the range 1-100 microM. Crystal structures of syngeneic TCRs bound to peptide major histocompatibility complex (pMHC) antigens exhibit a conserved mode of binding characterised by a distinct diagonal binding geometry, with poor shape complementarity (SC) between receptor and ligand. Here, we report the structures of three in vitro affinity enhanced TCRs that recognise the pMHC tumour epitope NY-ESO(157-165) (SLLMWITQC). These crystal structures reveal that the docking mode for the high affinity TCRs is identical to that reported for the parental wild-type TCR, with only subtle changes in the mutated complementarity determining regions (CDRs) that form contacts with pMHC; both CDR2 and CDR3 mutations act synergistically to improve the overall affinity. Comparison of free and bound TCR structures for both wild-type and a CDR3 mutant reveal an induced fit mechanism arising from restructuring of CDR3 loops which allows better peptide binding. Overall, an increased interface area, improved SC and additional H-bonding interactions are observed, accounting for the increase in affinity. Most notably, there is a marked increase in the SC for the central methionine and tryptophan peptide motif over the native TCR.

Crystal structures of high affinity human T-cell receptors bound to peptide major histocompatibility complex reveal native diagonal binding geometry.,Sami M, Rizkallah PJ, Dunn S, Molloy P, Moysey R, Vuidepot A, Baston E, Todorov P, Li Y, Gao F, Boulter JM, Jakobsen BK Protein Eng Des Sel. 2007 Aug;20(8):397-403. Epub 2007 Jul 20. PMID:17644531[5]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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Citations
7 reviews cite this structure
The molecular basis of TCR germline bias for MHC is surprisingly simple.
Garcia et al. (2009)
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See Also

References

  1. ↑ Nikolich-Zugich J, Slifka MK, Messaoudi I. The many important facets of T-cell repertoire diversity. Nat Rev Immunol. 2004 Feb;4(2):123-32. doi: 10.1038/nri1292. PMID:15040585 doi:http://dx.doi.org/10.1038/nri1292
  2. ↑ Brownlie RJ, Zamoyska R. T cell receptor signalling networks: branched, diversified and bounded. Nat Rev Immunol. 2013 Apr;13(4):257-69. doi: 10.1038/nri3403. PMID:23524462 doi:http://dx.doi.org/10.1038/nri3403
  3. ↑ Lefranc MP. Immunoglobulin and T Cell Receptor Genes: IMGT((R)) and the Birth and Rise of Immunoinformatics. Front Immunol. 2014 Feb 5;5:22. doi: 10.3389/fimmu.2014.00022. eCollection 2014. PMID:24600447 doi:http://dx.doi.org/10.3389/fimmu.2014.00022
  4. ↑ Rossjohn J, Gras S, Miles JJ, Turner SJ, Godfrey DI, McCluskey J. T cell antigen receptor recognition of antigen-presenting molecules. Annu Rev Immunol. 2015;33:169-200. doi: 10.1146/annurev-immunol-032414-112334., Epub 2014 Dec 10. PMID:25493333 doi:http://dx.doi.org/10.1146/annurev-immunol-032414-112334
  5. ↑ Sami M, Rizkallah PJ, Dunn S, Molloy P, Moysey R, Vuidepot A, Baston E, Todorov P, Li Y, Gao F, Boulter JM, Jakobsen BK. Crystal structures of high affinity human T-cell receptors bound to peptide major histocompatibility complex reveal native diagonal binding geometry. Protein Eng Des Sel. 2007 Aug;20(8):397-403. Epub 2007 Jul 20. PMID:17644531 doi:http://dx.doi.org/10.1093/protein/gzm033

Contents


PDB ID 2pyf

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