View source for 4o2c


==An Nt-acetylated peptide complexed with HLA-B*3901==
<StructureSection load='4o2c' size='340' side='right'caption='[[4o2c]], [[Resolution|resolution]] 1.80&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[4o2c]] 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=4O2C OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4O2C 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]] 1.802&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=ACE:ACETYL+GROUP'>ACE</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=4o2c FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4o2c OCA], [https://pdbe.org/4o2c PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4o2c RCSB], [https://www.ebi.ac.uk/pdbsum/4o2c PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4o2c ProSAT]</span></td></tr>
</table>
== Disease ==
[https://www.uniprot.org/uniprot/HLAB_HUMAN HLAB_HUMAN] Giant cell arteritis;Takayasu arteritis;Pulmonary arterial hypertension associated with connective tissue disease;Stevens-Johnson syndrome;Behcet disease;Reactive arthritis;NON RARE IN EUROPE: Ankylosing spondylitis. Disease susceptibility is associated with variants affecting the gene represented in this entry. Increased susceptibility to Stevens-Johnson syndrome is conferred by allele B*15:02.<ref>PMID:15057820</ref>   Disease susceptibility is associated with variants affecting the gene represented in this entry. A restricted number of HLA-B*27 subtypes can be associated with ankylosing spondylitis and other B*27-related diseases, and an elevated frequency of the B*27:02 allele in ankylosing spondylitis patients is identified. The allele B*27:07 seems to have a protective role in some populations because it was found only in the healthy controls.<ref>PMID:15603872</ref>   There is evidence that HLA-B*51 is associated with susceptibility to Behcet disease (BD). However, it is not certain whether HLA-B*51 itself or a closely linked gene is responsible for susceptibility. The world distribution of HLA-B*51 in healthy people corresponds to the global distribution of BD; in Southern hemisphere countries (Africa, South Pacific, etc.) and in some parts of Europe, the prevalence of HLA-B*51 in healthy people is low or null, corresponding to a low prevalence of BD. The wide variation that exists in the relative risk of HLA-B*51 would support other nongenetic risk factors.<ref>PMID:23291587</ref>   The presence of allele B*57:01 is associated with increased susceptibility to abacavir hypersensitivity [MIM:[https://omim.org/entry/142830 142830] in HIV-1 patients.<ref>PMID:11888582</ref>   Allele group B*08 is associated with increased susceptibility to rheumatoid arthritis, where affected individuals have antibodies to cyclic citrullinated peptide (anti-CCP-positive rheumatoid arthritis).<ref>PMID:22286218</ref> 
== Function ==
[https://www.uniprot.org/uniprot/HLAB_HUMAN HLAB_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-B-restricted CD8-positive T cells, guiding antigen-specific T cell immune response to eliminate infected or transformed cells (PubMed:23209413, PubMed:25808313, PubMed:29531227, PubMed:9620674). 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:18991276, PubMed:7743181). 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:24600035, PubMed:29531227, PubMed:9620674). Typically presents intracellular peptide antigens of 8 to 13 amino acids that arise from cytosolic proteolysis via constitutive proteasome and IFNG-induced immunoproteasome (PubMed:23209413). Can bind different peptides containing allele-specific binding motifs, which are mainly defined by anchor residues at position 2 and 9 (PubMed:25808313, PubMed:29531227).<ref>PMID:18991276</ref> <ref>PMID:23209413</ref> <ref>PMID:24600035</ref> <ref>PMID:25808313</ref> <ref>PMID:29531227</ref> <ref>PMID:7743181</ref> <ref>PMID:9620674</ref>   Allele B*07:02: Displays peptides sharing a common signature motif, namely a Pro residue at position 2 and mainly a Leu anchor residue at the C-terminus (PubMed:7743181). Presents a long peptide (APRGPHGGAASGL) derived from the cancer-testis antigen CTAG1A/NY-ESO-1, eliciting a polyclonal CD8-positive T cell response against tumor cells (PubMed:29531227). Presents viral epitopes derived from HIV-1 gag-pol (TPQDLNTML) and Nef (RPQVPLRPM) (PubMed:25808313). Presents an immunodominant epitope derived from SARS-CoV-2 N/nucleoprotein (SPRWYFYYL) (PubMed:32887977). Displays self-peptides including a peptide derived from the signal sequence of HLA-DPB1 (APRTVALTA) (PubMed:7743181).<ref>PMID:25808313</ref> <ref>PMID:29531227</ref> <ref>PMID:32887977</ref> <ref>PMID:7743181</ref>   Allele B*08:01: Presents to CD8-positive T cells viral epitopes derived from EBV/HHV-4 EBNA3 (QAKWRLQTL), eliciting cytotoxic T cell response.<ref>PMID:9620674</ref>   Allele B*13:02: Presents multiple HIV-1 epitopes derived from gag (RQANFLGKI, GQMREPRGSDI), nef (RQDILDLWI), gag-pol (RQYDQILIE, GQGQWTYQI) and rev (LQLPPLERL), all having in common a Gln residue at position 2 and mainly hydrophobic amino acids Leu, Ile or Val at the C-terminus. Associated with succesful control of HIV-1 infection.<ref>PMID:17251285</ref>   Allele B*18:01: Preferentially presents octomeric and nonameric peptides sharing a common motif, namely a Glu at position 2 and Phe or Tyr anchor residues at the C-terminus (PubMed:14978097, PubMed:18991276, PubMed:23749632). Presents an EBV/HHV-4 epitope derived from BZLF1 (SELEIKRY) (PubMed:23749632). May present to CD8-positive T cells an antigenic peptide derived from MAGEA3 (MEVDPIGHLY), triggering an anti-tumor immune response (PubMed:12366779). May display a broad repertoire of self-peptides with a preference for peptides derived from RNA-binding proteins (PubMed:14978097).<ref>PMID:12366779</ref> <ref>PMID:14978097</ref> <ref>PMID:18991276</ref> <ref>PMID:23749632</ref>   Allele B*27:05: Presents to CD8-positive T cells immunodominant viral epitopes derived from HCV POLG (ARMILMTHF), HIV-1 gag (KRWIILGLNK), IAV NP (SRYWAIRTR), SARS-CoV-2 N/nucleoprotein (QRNAPRITF), EBV/HHV-4 EBNA4 (HRCQAIRKK) and EBV/HHV-4 EBNA6 (RRIYDLIEL), conferring longterm protection against viral infection (PubMed:15113903, PubMed:18385228, PubMed:19139562, PubMed:32887977, PubMed:9620674). Can present self-peptides derived from cytosolic and nuclear proteins. All peptides carry an Arg at position 2 (PubMed:1922338). The peptide-bound form interacts with NK cell inhibitory receptor KIR3DL1 and inhibits NK cell activation in a peptide-specific way, being particularly sensitive to the nature of the amino acid side chain at position 8 of the antigenic peptide (PubMed:15657948, PubMed:8879234). KIR3DL1 fails to recognize HLA-B*27:05 in complex with B2M and EBV/HHV-4 EBNA6 (RRIYDLIEL) peptide, which can lead to increased activation of NK cells during infection (PubMed:15657948). May present an altered repertoire of peptides in the absence of TAP1-TAP2 and TAPBPL (PubMed:9620674).<ref>PMID:15113903</ref> <ref>PMID:15657948</ref> <ref>PMID:18385228</ref> <ref>PMID:19139562</ref> <ref>PMID:1922338</ref> <ref>PMID:8879234</ref> <ref>PMID:9620674</ref>   Allele B*40:01: Presents immunodominant viral epitopes derived from EBV/HHV-4 LMP2 (IEDPPFNSL) and SARS-CoV-2 N/nucleoprotein (MEVTPSGTWL), triggering memory CD8-positive T cell response (PubMed:18991276, PubMed:32887977). Displays self-peptides sharing a signature motif, namely a Glu at position 2 and a Leu anchor residue at the C-terminus (PubMed:18991276).<ref>PMID:18991276</ref> <ref>PMID:32887977</ref>   Allele B*41:01: Displays self-peptides sharing a signature motif, namely a Glu at position 2 and Ala or Pro anchor residues at the C-terminus.<ref>PMID:18991276</ref>   Allele B*44:02: Presents immunodominant viral epitopes derived from EBV/HHV-4 EBNA4 (VEITPYKPTW) and EBNA6 (AEGGVGWRHW, EENLLDFVRF), triggering memory CD8-positive T cell response (PubMed:18991276, PubMed:9620674). Displays self-peptides sharing a signature motif, namely a Glu at position 2 and Phe, Tyr or Trp anchor residues at the C-terminus (PubMed:18991276).<ref>PMID:18991276</ref> <ref>PMID:9620674</ref>   Allele B*45:01: Displays self-peptides sharing a signature motif, namely a Glu at position 2 and Ala or Pro anchor residues at the C-terminus.<ref>PMID:18991276</ref>   Allele B*46:01: Preferentially presents nonameric peptides sharing a signature motif, namely Ala and Leu at position 2 and Tyr, Phe, Leu, or Met anchor residues at the C-terminus. The peptide-bound form interacts with KIR2DL3 and inhibits NK cell cytotoxic response in a peptide-specific way.<ref>PMID:28514659</ref>   Allele B*47:01: Displays self-peptides sharing a signature motif, namely an Asp at position 2 and Leu or Met anchor residues at the C-terminus.<ref>PMID:18991276</ref>   Allele B*49:01: Displays self-peptides sharing a signature motif, namely a Glu at position 2 and Ile or Val anchor residues at the C-terminus.<ref>PMID:18991276</ref>   Allele B*50:01: Displays self-peptides sharing a signature motif, namely a Glu at position 2 and Ala or Pro anchor residues at the C-terminus.<ref>PMID:18991276</ref>   Allele B*51:01: Presents an octomeric HIV-1 epitope derived from gag-pol (TAFTIPSI) to the public TRAV17/TRBV7-3 TCR clonotype, strongly suppressing HIV-1 replication.<ref>PMID:24600035</ref>   Allele B*54:01: Displays peptides sharing a common signature motif, namely a Pro residue at position 2 and Ala anchor residue at the C-terminus.<ref>PMID:7743181</ref>   Allele B*55:01: Displays peptides sharing a common signature motif, namely a Pro residue at position 2 and Ala anchor residue at the C-terminus.<ref>PMID:7743181</ref>   Allele B*56:01: Displays peptides sharing a common signature motif, namely a Pro residue at position 2 and Ala anchor residue at the C-terminus.<ref>PMID:7743181</ref>   Allele B*57:01: The peptide-bound form recognizes KIR3DL1 and inhibits NK cell cytotoxic response. Presents HIV gag peptides (immunodominant KAFSPEVIPMF and subdominant KALGPAATL epitopes) predominantly to CD8-positive T cell clones expressing a TRAV41-containing TCR, triggering HLA-B-restricted T cell responses.<ref>PMID:22020283</ref> <ref>PMID:25480565</ref> <ref>PMID:34228645</ref>   Allele B*67:01: Displays peptides sharing a common signature motif, namely a Pro residue at position 2 and Leu anchor residue at the C-terminus.<ref>PMID:7743181</ref> 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
As one of the most common posttranslational modifications (PTMs) of eukaryotic proteins, N(alpha)-terminal acetylation (Nt-acetylation) generates a class of N(alpha)-acetylpeptides that are known to be presented by MHC class I at the cell surface. Although such PTM plays a pivotal role in adjusting proteolysis, the molecular basis for the presentation and T cell recognition of N(alpha)-acetylpeptides remains largely unknown. In this study, we determined a high-resolution crystallographic structure of HLA (HLA)-B*3901 complexed with an N(alpha)-acetylpeptide derived from natural cellular processing, also in comparison with the unmodified-peptide complex. Unlike the alpha-amino-free P1 residues of unmodified peptide, of which the alpha-amino group inserts into pocket A of the Ag-binding groove, the N(alpha)-linked acetyl of the acetylated P1-Ser protrudes out of the groove for T cell recognition. Moreover, the Nt-acetylation not only alters the conformation of the peptide but also switches the residues in the alpha1-helix of HLA-B*3901, which may impact the T cell engagement. The thermostability measurements of complexes between N(alpha)-acetylpeptides and a series of MHC class I molecules derived from different species reveal reduced stability. Our findings provide the insight into the mode of N(alpha)-acetylpeptide-specific presentation by classical MHC class I molecules and shed light on the potential of acetylepitope-based immune intervene and vaccine development.

Nalpha-terminal acetylation for T cell recognition: molecular basis of MHC class I-restricted nalpha-acetylpeptide presentation.,Sun M, Liu J, Qi J, Tefsen B, Shi Y, Yan J, Gao GF J Immunol. 2014 Jun 15;192(12):5509-19. doi: 10.4049/jimmunol.1400199. Epub 2014 , May 14. PMID:24829406<ref>PMID:24829406</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 4o2c" 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: Gao GF]]
[[Category: Liu J]]
[[Category: Qi J]]
[[Category: Shi Y]]
[[Category: Sun M]]
[[Category: Tefsen B]]
[[Category: Yan J]]