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== Function == | == Function == | ||
[[http://www.uniprot.org/uniprot/1A02_HUMAN 1A02_HUMAN]] Involved in the presentation of foreign antigens to the immune system. [[http://www.uniprot.org/uniprot/B2MG_HUMAN B2MG_HUMAN]] 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/1A02_HUMAN 1A02_HUMAN]] Involved in the presentation of foreign antigens to the immune system. [[http://www.uniprot.org/uniprot/B2MG_HUMAN B2MG_HUMAN]] Component of the class I major histocompatibility complex (MHC). Involved in the presentation of peptide antigens to the immune system. | ||
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== Publication Abstract from PubMed == | |||
Peptide antigen presentation by major histocompatibility complex (MHC) class I proteins initiates CD8(+) T cell-mediated immunity against pathogens and cancers. MHC I molecules typically bind peptides with 9 amino acids in length with both ends tucked inside the major A and F binding pockets. It has been known for a while that longer peptides can also bind by either bulging out of the groove in the middle of the peptide or by binding in a zigzag fashion inside the groove. In a recent study, we identified an alternative binding conformation of naturally occurring peptides from Toxoplasma gondii bound by HLA-A*02:01. These peptides were extended at the C terminus (POmega) and contained charged amino acids not more than 3 residues after the anchor amino acid at POmega, which enabled them to open the F pocket and expose their C-terminal extension into the solvent. Here, we show that the mechanism of F pocket opening is dictated by the charge of the first charged amino acid found within the extension. Although positively charged amino acids result in the Tyr-84 swing, amino acids that are negatively charged induce a not previously described Lys-146 lift. Furthermore, we demonstrate that the peptides with alternative binding modes have properties that fit very poorly to the conventional MHC class I pathway and suggest they are presented via alternative means, potentially including cross-presentation via the MHC class II pathway. | |||
Unconventional Peptide Presentation by Major Histocompatibility Complex (MHC) Class I Allele HLA-A*02:01: BREAKING CONFINEMENT.,Remesh SG, Andreatta M, Ying G, Kaever T, Nielsen M, McMurtrey C, Hildebrand W, Peters B, Zajonc DM J Biol Chem. 2017 Mar 31;292(13):5262-5270. doi: 10.1074/jbc.M117.776542. Epub, 2017 Feb 8. PMID:28179428<ref>PMID:28179428</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
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==See Also== | |||
*[[Beta-2 microglobulin|Beta-2 microglobulin]] | |||
== References == | == References == | ||
<references/> | <references/> | ||
Revision as of 09:24, 9 May 2018
Structure of HLA-A2:01 with peptide G9LStructure of HLA-A2:01 with peptide G9L
Structural highlights
Disease[B2MG_HUMAN] Defects in B2M are the cause of hypercatabolic hypoproteinemia (HYCATHYP) [MIM:241600]. Affected individuals show marked reduction in serum concentrations of immunoglobulin and albumin, probably due to rapid degradation.[1] Note=Beta-2-microglobulin may adopt the fibrillar configuration of amyloid in certain pathologic states. The capacity to assemble into amyloid fibrils is concentration dependent. Persistently high beta(2)-microglobulin serum levels lead to amyloidosis in patients on long-term hemodialysis.[2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] Function[1A02_HUMAN] Involved in the presentation of foreign antigens to the immune system. [B2MG_HUMAN] Component of the class I major histocompatibility complex (MHC). Involved in the presentation of peptide antigens to the immune system. Publication Abstract from PubMedPeptide antigen presentation by major histocompatibility complex (MHC) class I proteins initiates CD8(+) T cell-mediated immunity against pathogens and cancers. MHC I molecules typically bind peptides with 9 amino acids in length with both ends tucked inside the major A and F binding pockets. It has been known for a while that longer peptides can also bind by either bulging out of the groove in the middle of the peptide or by binding in a zigzag fashion inside the groove. In a recent study, we identified an alternative binding conformation of naturally occurring peptides from Toxoplasma gondii bound by HLA-A*02:01. These peptides were extended at the C terminus (POmega) and contained charged amino acids not more than 3 residues after the anchor amino acid at POmega, which enabled them to open the F pocket and expose their C-terminal extension into the solvent. Here, we show that the mechanism of F pocket opening is dictated by the charge of the first charged amino acid found within the extension. Although positively charged amino acids result in the Tyr-84 swing, amino acids that are negatively charged induce a not previously described Lys-146 lift. Furthermore, we demonstrate that the peptides with alternative binding modes have properties that fit very poorly to the conventional MHC class I pathway and suggest they are presented via alternative means, potentially including cross-presentation via the MHC class II pathway. Unconventional Peptide Presentation by Major Histocompatibility Complex (MHC) Class I Allele HLA-A*02:01: BREAKING CONFINEMENT.,Remesh SG, Andreatta M, Ying G, Kaever T, Nielsen M, McMurtrey C, Hildebrand W, Peters B, Zajonc DM J Biol Chem. 2017 Mar 31;292(13):5262-5270. doi: 10.1074/jbc.M117.776542. Epub, 2017 Feb 8. PMID:28179428[15] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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