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== Function == | == Function == | ||
[[http://www.uniprot.org/uniprot/B2MG_MOUSE B2MG_MOUSE]] Component of the class I major histocompatibility complex (MHC). Involved in the presentation of peptide antigens to the immune system. | [[http://www.uniprot.org/uniprot/B2MG_MOUSE B2MG_MOUSE]] Component of the class I major histocompatibility complex (MHC). Involved in the presentation of peptide antigens to the immune system. | ||
| + | <div style="background-color:#fffaf0;"> | ||
| + | == Publication Abstract from PubMed == | ||
| + | Endoplasmic reticulum aminopeptidase 1 (ERAP1) and ERAP2 process N-terminally extended antigenic precursors for optimal loading onto major histocompatibility complex class I (MHC I) molecules. We and others have demonstrated that ERAP1 processes peptides bound to MHC I, but the underlying mechanism is unknown. To this end, we utilized single-chain trimers (SCT) of the ovalbumin-derived epitope SIINFEKL (SL8) tethered to the H2-Kb MHC I determinant from mouse and introduced three substitutions, E63A, K66A, and W167A, at the A-pocket of the peptide-binding groove in the MHC I heavy chain, which interact with the N termini of peptides. These variants significantly decreased SL8-presenting SCT at the cell surface in the presence of ERAP1, but did not affect overall SCT expression, indicating that ERAP1 trims the SL8 N terminus. Comparison of the X-ray crystal structures of WT and three variant SCTs revealed only minor perturbations of the peptide-binding domain in the variants. However, molecular dynamics simulations suggested that SL8 can dissociate partially within a sub-microsecond timescale, exposing its N terminus to the solvent. We also found that the C terminus of MHC I-bound SL8 remains deeply buried in the F-pocket of MHC I. Furthermore, free-energy calculations revealed that the three SCT variants exhibit lower free-energy barriers of N terminus dissociation than the WT Kb. Taken together, our results are consistent with a previously observed model in which the partial dissociation of bound peptides from MHC I exposes their N terminus to trimming by ERAP1, while their C terminus is anchored at the F-pocket. | ||
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| + | The partial dissociation of MHC class I bound peptides exposes their N terminus to trimming by endoplasmic reticulum aminopeptidase 1.,Papakyriakou A, Reeves E, Beton M, Mikolajek H, Douglas L, Cooper G, Elliott T, Werner JM, James E J Biol Chem. 2018 Mar 29. pii: RA117.000313. doi: 10.1074/jbc.RA117.000313. PMID:29599287<ref>PMID:29599287</ref> | ||
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| + | From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | ||
| + | </div> | ||
| + | <div class="pdbe-citations 5oqh" style="background-color:#fffaf0;"></div> | ||
| + | == References == | ||
| + | <references/> | ||
__TOC__ | __TOC__ | ||
</StructureSection> | </StructureSection> | ||
Revision as of 05:47, 30 May 2018
Crystal Structure of a disulfide trapped single chain trimer composed of the MHC I heavy chain H-2Kb Y84C K66A mutant, beta-2microglobulin, and ovalbumin-derived peptide
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Categories: Lk3 transgenic mice | Beton, M E | Mikolajek, H | Werner, J M | Antigen | Diagnosis | Epitope | Immune system | Major histocompatibility complex | Mice | Model | Molecular | Molecular conformation | Peptide | Receptor | T-cell | T-lymphocyte | Vaccine
