The complex between high-affinity TCR DMF5(alpha-D26Y,beta-L98W) and human Class I MHC HLA-A2 with the bound MART-1(27-35)peptideThe complex between high-affinity TCR DMF5(alpha-D26Y,beta-L98W) and human Class I MHC HLA-A2 with the bound MART-1(27-35)peptide

Structural highlights

6d78 is a 5 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 2.347Å
Resources:FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

MAR1_HUMAN Involved in melanosome biogenesis by ensuring the stability of GPR143. Plays a vital role in the expression, stability, trafficking, and processing of melanocyte protein PMEL, which is critical to the formation of stage II melanosomes.[1] [2]

Publication Abstract from PubMed

T cell receptors (TCRs) have emerged as a new class of immunological therapeutics. However, though antigen specificity is a hallmark of adaptive immunity, TCRs themselves do not possess the high specificity of monoclonal antibodies. Although a necessary function of T cell biology, the resulting cross-reactivity presents a significant challenge for TCR-based therapeutic development, as it creates the potential for off-target recognition and immune toxicity. Efforts to enhance TCR specificity by mimicking the antibody maturation process and enhancing affinity can inadvertently exacerbate TCR cross-reactivity. Here we demonstrate this concern by showing that even peptide-targeted mutations in the TCR can introduce new reactivities against peptides that bear similarity to the original target. To counteract this, we explored a novel structure-guided approach for enhancing TCR specificity independent of affinity. Tested with the MART-1-specific TCR DMF5, our approach had a small but discernible impact on cross-reactivity toward MART-1 homologs yet was able to eliminate DMF5 cross-recognition of more divergent, unrelated epitopes. Our study provides a proof of principle for the use of advanced structure-guided design techniques for improving TCR specificity, and it suggests new ways forward for enhancing TCRs for therapeutic use.

Improving T Cell Receptor On-Target Specificity via Structure-Guided Design.,Hellman LM, Foley KC, Singh NK, Alonso JA, Riley TP, Devlin JR, Ayres CM, Keller GLJ, Zhang Y, Vander Kooi CW, Nishimura MI, Baker BM Mol Ther. 2019 Feb 6;27(2):300-313. doi: 10.1016/j.ymthe.2018.12.010. Epub 2018, Dec 14. PMID:30617019[3]

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

See Also

References

  1. Hoashi T, Watabe H, Muller J, Yamaguchi Y, Vieira WD, Hearing VJ. MART-1 is required for the function of the melanosomal matrix protein PMEL17/GP100 and the maturation of melanosomes. J Biol Chem. 2005 Apr 8;280(14):14006-16. Epub 2005 Jan 28. PMID:15695812 doi:10.1074/jbc.M413692200
  2. Giordano F, Bonetti C, Surace EM, Marigo V, Raposo G. The ocular albinism type 1 (OA1) G-protein-coupled receptor functions with MART-1 at early stages of melanogenesis to control melanosome identity and composition. Hum Mol Genet. 2009 Dec 1;18(23):4530-45. doi: 10.1093/hmg/ddp415. Epub 2009 Aug , 28. PMID:19717472 doi:10.1093/hmg/ddp415
  3. Hellman LM, Foley KC, Singh NK, Alonso JA, Riley TP, Devlin JR, Ayres CM, Keller GLJ, Zhang Y, Vander Kooi CW, Nishimura MI, Baker BM. Improving T Cell Receptor On-Target Specificity via Structure-Guided Design. Mol Ther. 2019 Feb 6;27(2):300-313. doi: 10.1016/j.ymthe.2018.12.010. Epub 2018, Dec 14. PMID:30617019 doi:http://dx.doi.org/10.1016/j.ymthe.2018.12.010

6d78, resolution 2.35Å

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