View source for 5meq


==Human Leukocyte Antigen A02 presenting ILAKFLHTL==
<StructureSection load='5meq' size='340' side='right'caption='[[5meq]], [[Resolution|resolution]] 2.27&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[5meq]] is a 3 chain structure with sequence from [https://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=5MEQ OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=5MEQ FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2.27&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=EDO:1,2-ETHANEDIOL'>EDO</scene>, <scene name='pdbligand=SO4:SULFATE+ION'>SO4</scene></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=5meq FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=5meq OCA], [https://pdbe.org/5meq PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=5meq RCSB], [https://www.ebi.ac.uk/pdbsum/5meq PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=5meq ProSAT]</span></td></tr>
</table>
== Disease ==
[https://www.uniprot.org/uniprot/HLAA_HUMAN HLAA_HUMAN] Selection of immunotherapy in solid cancer;Birdshot chorioretinopathy;Prediction of phenytoin or carbamazepine toxicity. Alleles A*02:01 and A*24:02 are associated with increased susceptibility to diabetes mellitus, insulin-dependent (IDDM) (PubMed:22245737, PubMed:18802479, PubMed:16731854, PubMed:22522618). In a glucose-dependent way, allele A*02:01 may aberrantly present the signal peptide of preproinsulin (ALWGPDPAAA) on the surface of pancreatic beta cells to autoreactive CD8-positive T cells, potentially driving T-cell mediated cytotoxicity in pancreatic islets (PubMed:22245737, PubMed:18802479). Allele A*24:02 may present the signal peptide of preproinsulin (LWMRLLPLL) and contribute to acute pancreatic beta-cell destruction and early onset of IDDM (PubMed:16731854, PubMed:22522618).<ref>PMID:16731854</ref> <ref>PMID:18802479</ref> <ref>PMID:22245737</ref> <ref>PMID:22522618</ref>   Allele A*03:01 is associated with increased susceptibility to multiple sclerosis (MS), an autoimmune disease of the central nervous system (PubMed:10746785). May contribute to the initiation phase of the disease by presenting myelin PLP1 self-peptide (KLIETYFSK) to autoreactive CD8-positive T cells capable of initiating the first autoimmune attacks (PubMed:18953350).<ref>PMID:10746785</ref> <ref>PMID:18953350</ref>   Allele A*26:01 is associated with increased susceptibility to Behcet disease (BD) in the Northeast Asian population. Especially in the HLA-B*51-negative BD populations, HLA-A*26 is significantly associated with the onset of BD.<ref>PMID:30872678</ref>   Allele A*29:02 is associated with increased susceptibility to birdshot chorioretinopathy (BSCR). May aberrantly present retinal autoantigens and induce autoimmune uveitis.<ref>PMID:1728143</ref> 
== Function ==
[https://www.uniprot.org/uniprot/HLAA_HUMAN HLAA_HUMAN] Antigen-presenting major histocompatibility complex class I (MHCI) molecule. In complex with B2M/beta 2 microglobulin displays primarily viral and tumor-derived peptides on antigen-presenting cells for recognition by alpha-beta T cell receptor (TCR) on HLA-A-restricted CD8-positive T cells, guiding antigen-specific T cell immune response to eliminate infected or transformed cells (PubMed:2456340, PubMed:2784196, PubMed:1402688, PubMed:7504010, PubMed:9862734, PubMed:10449296, PubMed:12138174, PubMed:12393434, PubMed:15893615, PubMed:17189421, PubMed:19543285, PubMed:21498667, PubMed:24192765, PubMed:7694806, PubMed:24395804, PubMed:28250417). May also present self-peptides derived from the signal sequence of secreted or membrane proteins, although T cells specific for these peptides are usually inactivated to prevent autoreactivity (PubMed:25880248, PubMed:7506728, PubMed:7679507). Both the peptide and the MHC molecule are recognized by TCR, the peptide is responsible for the fine specificity of antigen recognition and MHC residues account for the MHC restriction of T cells (PubMed:12796775, PubMed:18275829, PubMed:19542454, PubMed:28250417). Typically presents intracellular peptide antigens of 8 to 13 amino acids that arise from cytosolic proteolysis via IFNG-induced immunoproteasome or via endopeptidase IDE/insulin-degrading enzyme (PubMed:17189421, PubMed:20364150, PubMed:17079320, PubMed:26929325, PubMed:27049119). Can bind different peptides containing allele-specific binding motifs, which are mainly defined by anchor residues at position 2 and 9 (PubMed:7504010, PubMed:9862734).<ref>PMID:10449296</ref> <ref>PMID:12138174</ref> <ref>PMID:12393434</ref> <ref>PMID:12796775</ref> <ref>PMID:1402688</ref> <ref>PMID:15893615</ref> <ref>PMID:17079320</ref> <ref>PMID:17189421</ref> <ref>PMID:18275829</ref> <ref>PMID:19542454</ref> <ref>PMID:19543285</ref> <ref>PMID:20364150</ref> <ref>PMID:21498667</ref> <ref>PMID:24192765</ref> <ref>PMID:24395804</ref> <ref>PMID:2456340</ref> <ref>PMID:25880248</ref> <ref>PMID:26929325</ref> <ref>PMID:27049119</ref> <ref>PMID:2784196</ref> <ref>PMID:28250417</ref> <ref>PMID:7504010</ref> <ref>PMID:7506728</ref> <ref>PMID:7679507</ref> <ref>PMID:7694806</ref> <ref>PMID:9862734</ref>   Allele A*01:01: Presents a restricted peptide repertoire including viral epitopes derived from IAV NP/nucleoprotein (CTELKLSDY), IAV PB1/polymerase basic protein 1 (VSDGGPNLY), HAdV-11 capsid L3/hexon protein (LTDLGQNLLY), SARS-CoV-2 3a/ORF3a (FTSDYYQLY) as well as tumor peptide antigens including MAGE1 (EADPTGHSY), MAGEA3 (EVDPIGHLY) and WT1 (TSEKRPFMCAY), all having in common a canonical motif with a negatively charged Asp or Glu residue at position 3 and a Tyr anchor residue at the C-terminus (PubMed:1402688, PubMed:7504010, PubMed:17189421, PubMed:20364150, PubMed:25880248, PubMed:30530481, PubMed:19177349, PubMed:24395804, PubMed:26758806, PubMed:32887977). A number of HLA-A*01:01-restricted peptides carry a post-translational modification with oxidation and N-terminal acetylation being the most frequent (PubMed:25880248). Fails to present highly immunogenic peptides from the EBV latent antigens (PubMed:18779413).<ref>PMID:1402688</ref> <ref>PMID:17189421</ref> <ref>PMID:18779413</ref> <ref>PMID:19177349</ref> <ref>PMID:20364150</ref> <ref>PMID:24395804</ref> <ref>PMID:25880248</ref> <ref>PMID:26758806</ref> <ref>PMID:30530481</ref> <ref>PMID:7504010</ref>   Allele A*02:01: A major allele in human populations, presents immunodominant viral epitopes derived from IAV M/matrix protein 1 (GILGFVFTL), HIV-1 env (TLTSCNTSV), HIV-1 gag-pol (ILKEPVHGV), HTLV-1 Tax (LLFGYPVYV), HBV C/core antigen (FLPSDFFPS), HCMV UL83/pp65 (NLVPMVATV) as well as tumor peptide antigens including MAGEA4 (GVYDGREHTV), WT1 (RMFPNAPYL) and CTAG1A/NY-ESO-1 (SLLMWITQC), all having in common hydrophobic amino acids at position 2 and at the C-terminal anchors.<ref>PMID:11502003</ref> <ref>PMID:12138174</ref> <ref>PMID:12796775</ref> <ref>PMID:17079320</ref> <ref>PMID:18275829</ref> <ref>PMID:19542454</ref> <ref>PMID:20619457</ref> <ref>PMID:22245737</ref> <ref>PMID:26929325</ref> <ref>PMID:2784196</ref> <ref>PMID:28250417</ref> <ref>PMID:7694806</ref> <ref>PMID:7935798</ref> <ref>PMID:8630735</ref> <ref>PMID:8805302</ref> <ref>PMID:8906788</ref> <ref>PMID:9177355</ref>   Allele A*03:01: Presents viral epitopes derived from IAV NP (ILRGSVAHK), HIV-1 nef (QVPLRPMTYK), HIV-1 gag-pol (AIFQSSMTK), SARS-CoV-2 N/nucleoprotein (KTFPPTEPK) as well as tumor peptide antigens including PMEL (LIYRRRLMK), NODAL (HAYIQSLLK), TRP-2 (RMYNMVPFF), all having in common hydrophobic amino acids at position 2 and Lys or Arg anchor residues at the C-terminus (PubMed:7504010, PubMed:7679507, PubMed:9862734, PubMed:19543285, PubMed:21943705, PubMed:2456340, PubMed:32887977). May also display spliced peptides resulting from the ligation of two separate proteasomal cleavage products that are not contiguous in the parental protein (PubMed:27049119).<ref>PMID:19543285</ref> <ref>PMID:21943705</ref> <ref>PMID:2456340</ref> <ref>PMID:27049119</ref> <ref>PMID:7504010</ref> <ref>PMID:7679507</ref> <ref>PMID:9862734</ref>   Allele A*11:01: Presents several immunodominant epitopes derived from HIV-1 gag-pol and HHV-4 EBNA4, containing the peptide motif with Val, Ile, Thr, Leu, Tyr or Phe at position 2 and Lys anchor residue at the C-terminus. Important in the control of HIV-1, EBV and HBV infections (PubMed:10449296). Presents an immunodominant epitope derived from SARS-CoV-2 N/nucleoprotein (KTFPPTEPK) (PubMed:32887977).<ref>PMID:10449296</ref> <ref>PMID:32887977</ref>   Allele A*23:01: Interacts with natural killer (NK) cell receptor KIR3DL1 and may contribute to functional maturation of NK cells and self-nonself discrimination during innate immune response.<ref>PMID:17182537</ref>   Allele A*24:02: Presents viral epitopes derived from HIV-1 nef (RYPLTFGWCF), EBV lytic- and latent-cycle antigens BRLF1 (TYPVLEEMF), BMLF1 (DYNFVKQLF) and LMP2 (IYVLVMLVL), SARS-CoV nucleocapsid/N (QFKDNVILL), as well as tumor peptide antigens including PRAME (LYVDSLFFL), all sharing a common signature motif, namely an aromatic residue Tyr or Phe at position 2 and a nonhydrophobic anchor residue Phe, Leu or Iso at the C-terminus (PubMed:9047241, PubMed:12393434, PubMed:24192765, PubMed:20844028). Interacts with natural killer (NK) cell receptor KIR3DL1 and may contribute to functional maturation of NK cells and self-nonself discrimination during innate immune response (PubMed:17182537, PubMed:18502829).<ref>PMID:12393434</ref> <ref>PMID:17182537</ref> <ref>PMID:18502829</ref> <ref>PMID:20844028</ref> <ref>PMID:24192765</ref> <ref>PMID:9047241</ref>   Allele A*26:01: Presents several epitopes derived from HIV-1 gag-pol (EVIPMFSAL, ETKLGKAGY) and env (LVSDGGPNLY), carrying as anchor residues preferentially Glu at position 1, Val or Thr at position 2 and Tyr at the C-terminus.<ref>PMID:15893615</ref>   Allele A*29:02: Presents peptides having a common motif, namely a Glu residue at position 2 and Tyr or Leu anchor residues at the C-terminus.<ref>PMID:8622959</ref>   Allele A*32:01: Interacts with natural killer (NK) cell receptor KIR3DL1 and may contribute to functional maturation of NK cells and self-nonself discrimination during innate immune response.<ref>PMID:17182537</ref>   Allele A*68:01: Presents viral epitopes derived from IAV NP (KTGGPIYKR) and HIV-1 tat (ITKGLGISYGR), having a common signature motif namely, Val or Thr at position 2 and positively charged residues Arg or Lys at the C-terminal anchor.<ref>PMID:1448153</ref> <ref>PMID:1448154</ref> <ref>PMID:2784196</ref>   Allele A*74:01: Presents immunodominant HIV-1 epitopes derived from gag-pol (GQMVHQAISPR, QIYPGIKVR) and rev (RQIHSISER), carrying an aliphatic residue at position 2 and Arg anchor residue at the C-terminus. May contribute to viral load control in chronic HIV-1 infection.<ref>PMID:21498667</ref> 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
T-cell cross-reactivity is essential for effective immune surveillance, but has also been implicated as a pathway to autoimmunity. Previous studies have demonstrated that T-cell receptors (TCRs) that focus on a minimal motif within the peptide are able to facilitate a high level of T-cell cross-reactivity. However, the structural database shows that most TCRs exhibit less focussed antigen binding involving contact with more peptide residues. To further explore the structural features that allow the clonally expressed TCR to functionally engage with multiple peptide-major histocompatibility complexes (pMHCs), we examined the ILA1 CD8+ T-cell clone that responds to a peptide sequence derived from human telomerase reverse transcriptase (hTERT). The ILA1 TCR contacted its pMHC with a broad peptide-binding footprint encompassing spatially distant peptide residues. Despite the lack of focused TCR-peptide binding , the ILA1 T-cell clone was still cross-reactive. Overall, the TCR-peptide contacts apparent in the structure correlated well with the level of degeneracy at different peptide positions. Thus, the ILA1 TCR was less tolerant of changes at peptide residues that were at, or adjacent to, key contact sites. This study provides new insights into the molecular mechanisms that control T-cell cross-reactivity, with important implications for pathogen surveillance, autoimmunity and transplant rejection.

Structural mechanism underpinning cross-reactivity of a CD8+ T-cell clone that recognises a peptide derived from human telomerase reverse transcriptase.,Cole DK, van den Berg HA, Lloyd A, Crowther MD, Beck K, Ekeruche-Makinde J, Miles JJ, Bulek AM, Dolton G, Schauenburg AJ, Wall A, Fuller A, Clement M, Laugel B, Rizkallah PJ, Wooldridge L, Sewell AK J Biol Chem. 2016 Nov 30. pii: jbc.M116.741603. PMID:27903649<ref>PMID:27903649</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 5meq" style="background-color:#fffaf0;"></div>

==See Also==
*[[Beta-2 microglobulin 3D structures|Beta-2 microglobulin 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Homo sapiens]]
[[Category: Large Structures]]
[[Category: Cole DK]]
[[Category: Crowther M]]
[[Category: Lloyd A]]
[[Category: Rizkallah PJ]]
[[Category: Sewell AK]]