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| | <StructureSection load='6a2b' size='340' side='right'caption='[[6a2b]], [[Resolution|resolution]] 2.80Å' scene=''> | | <StructureSection load='6a2b' size='340' side='right'caption='[[6a2b]], [[Resolution|resolution]] 2.80Å' scene=''> |
| | == Structural highlights == | | == Structural highlights == |
| - | <table><tr><td colspan='2'>[[6a2b]] is a 3 chain structure with sequence from [http://en.wikipedia.org/wiki/African_clawed_frog African clawed frog]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6A2B OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=6A2B FirstGlance]. <br> | + | <table><tr><td colspan='2'>[[6a2b]] is a 3 chain structure with sequence from [https://en.wikipedia.org/wiki/Xenopus_laevis Xenopus laevis]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6A2B OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=6A2B FirstGlance]. <br> |
| - | </td></tr><tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">b2m ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=8355 African clawed frog])</td></tr> | + | </td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2.8Å</td></tr> |
| - | <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=6a2b FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6a2b OCA], [http://pdbe.org/6a2b PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=6a2b RCSB], [http://www.ebi.ac.uk/pdbsum/6a2b PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=6a2b ProSAT]</span></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=6a2b FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6a2b OCA], [https://pdbe.org/6a2b PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=6a2b RCSB], [https://www.ebi.ac.uk/pdbsum/6a2b PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=6a2b ProSAT]</span></td></tr> |
| | </table> | | </table> |
| | == Function == | | == Function == |
| - | [[http://www.uniprot.org/uniprot/B2MG_XENLA B2MG_XENLA]] Component of the class I major histocompatibility complex (MHC). Involved in the presentation of peptide antigens to the immune system (By similarity). | + | [https://www.uniprot.org/uniprot/Q9TPA7_XENLA Q9TPA7_XENLA] |
| | <div style="background-color:#fffaf0;"> | | <div style="background-color:#fffaf0;"> |
| | == Publication Abstract from PubMed == | | == Publication Abstract from PubMed == |
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| | </div> | | </div> |
| | <div class="pdbe-citations 6a2b" style="background-color:#fffaf0;"></div> | | <div class="pdbe-citations 6a2b" style="background-color:#fffaf0;"></div> |
| | + | |
| | + | ==See Also== |
| | + | *[[Beta-2 microglobulin 3D structures|Beta-2 microglobulin 3D structures]] |
| | + | *[[MHC 3D structures|MHC 3D structures]] |
| | + | *[[MHC I 3D structures|MHC I 3D structures]] |
| | == References == | | == References == |
| | <references/> | | <references/> |
| | __TOC__ | | __TOC__ |
| | </StructureSection> | | </StructureSection> |
| - | [[Category: African clawed frog]] | |
| | [[Category: Large Structures]] | | [[Category: Large Structures]] |
| - | [[Category: Ma, L Z]] | + | [[Category: Xenopus laevis]] |
| - | [[Category: Xia, C]] | + | [[Category: Ma LZ]] |
| - | [[Category: Evolution]] | + | [[Category: Xia C]] |
| - | [[Category: Immune system]]
| + | |
| - | [[Category: Mhc i]]
| + | |
| - | [[Category: Xenopus laevi]]
| + | |
| Structural highlights
Function
Q9TPA7_XENLA
Publication Abstract from PubMed
The African clawed frog, Xenopus laevis, is a model species for amphibians. Before metamorphosis, tadpoles do not efficiently express the single classical MHC class I (MHC-I) molecule Xela-UAA, but after metamorphosis, adults express this molecule in abundance. To elucidate the Ag-presenting mechanism of Xela-UAA, in this study, the Xela-UAA structure complex (pXela-UAAg) bound with a peptide from a synthetic random peptide library was determined. The amino acid homology between the Xela-UAA and MHC-I sequences of different species is <45%, and these differences are fully reflected in the three-dimensional structure of pXela-UAAg. Because of polymorphisms and interspecific differences in amino acid sequences, pXela-UAAg forms a distinct peptide-binding groove and presents a unique peptide profile. The most important feature of pXela-UAAg is the two-amino acid insertion in the alpha2-helical region, which forms a protrusion of approximately 3.8 A that is involved in TCR docking. Comparison of peptide-MHC-I complex (pMHC-I) structures showed that only four amino acids in beta2-microglobulin that were bound to MHC-I are conserved in almost all jawed vertebrates, and the most unique feature in nonmammalian pMHC-I molecules is that the AB loop bound beta2-microglobulin. Additionally, the binding distance between pMHC-I and CD8 molecules in nonmammals is different from that in mammals. These unique features of pXela-UAAg provide enhanced knowledge of T cell immunity and bridge the knowledge gap regarding the coevolutionary progression of the MHC-I complex from aquatic to terrestrial species.
A Glimpse of the Peptide Profile Presentation by Xenopus laevis MHC Class I: Crystal Structure of pXela-UAA Reveals a Distinct Peptide-Binding Groove.,Ma L, Zhang N, Qu Z, Liang R, Zhang L, Zhang B, Meng G, Dijkstra JM, Li S, Xia MC J Immunol. 2019 Nov 27. pii: jimmunol.1900865. doi: 10.4049/jimmunol.1900865. PMID:31776204[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Ma L, Zhang N, Qu Z, Liang R, Zhang L, Zhang B, Meng G, Dijkstra JM, Li S, Xia MC. A Glimpse of the Peptide Profile Presentation by Xenopus laevis MHC Class I: Crystal Structure of pXela-UAA Reveals a Distinct Peptide-Binding Groove. J Immunol. 2019 Nov 27. pii: jimmunol.1900865. doi: 10.4049/jimmunol.1900865. PMID:31776204 doi:http://dx.doi.org/10.4049/jimmunol.1900865
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