6P2S

Structure of a nested set of N-terminally extended MHC I-peptides provide novel insights into antigen processing and presentation


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.65 Å
  • R-Value Free: 0.214 
  • R-Value Work: 0.204 
  • R-Value Observed: 0.205 

wwPDB Validation   3D Report Full Report


This is version 2.1 of the entry. See complete history


Literature

ERAP1 enzyme-mediated trimming and structural analyses of MHC I-bound precursor peptides yield novel insights into antigen processing and presentation.

Li, L.Batliwala, M.Bouvier, M.

(2019) J Biol Chem 294: 18534-18544

  • DOI: https://doi.org/10.1074/jbc.RA119.010102
  • Primary Citation of Related Structures:  
    6P23, 6P27, 6P2C, 6P2F, 6P2S

  • PubMed Abstract: 

    Endoplasmic reticulum aminopeptidase 1 (ERAP1) and ERAP2 critically shape the major histocompatibility complex I (MHC I) immunopeptidome. The ERAPs remove N-terminal residues from antigenic precursor peptides and generate optimal-length peptides ( i.e. 8-10-mers) to fit into the MHC class I groove. It is therefore intriguing that MHC class I molecules can present N-terminally extended peptides on the cell surface that can elicit CD8+ T-cell responses. This observation likely reflects gaps in our understanding of how antigens are processed by the ERAP enzymes. To better understand ERAPs' function in antigen processing, here we generated a nested set of N-terminally extended 10-20-mer peptides (RA) n AAKKKYCL covalently bound to the human leukocyte antigen (HLA)-B*0801. We used X-ray crystallography, thermostability assessments, and an ERAP1-trimming assay to characterize these complexes. The X-ray structures determined at 1.40-1.65 Å resolutions revealed that the residue extensions (RA) n unexpectedly protrude out of the A pocket of HLA-B*0801, whereas the AAKKKYCL core of all peptides adopts similar, bound conformations. HLA-B*0801 residue 62 was critical to open the A pocket. We also show that HLA-B*0801 and antigenic precursor peptides form stable complexes. Finally, ERAP1-mediated trimming of the MHC I-bound peptides required a minimal length of 14 amino acids. We propose a mechanistic model explaining how ERAP1-mediated trimming of MHC I-bound peptides in cells can generate peptides of canonical as well as noncanonical lengths that still serve as stable MHC I ligands. Our results provide a framework to better understand how the ERAP enzymes influence the MHC I immunopeptidome.


  • Organizational Affiliation

    Department of Microbiology and Immunology, University of Illinois, Chicago, Illinois 60612.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
MHC class I antigen276Homo sapiensMutation(s): 1 
Gene Names: HLA-B
UniProt & NIH Common Fund Data Resources
Find proteins for P01889 (Homo sapiens)
Explore P01889 
Go to UniProtKB:  P01889
PHAROS:  P01889
GTEx:  ENSG00000234745 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP01889
Sequence Annotations
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  • Reference Sequence
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Entity ID: 2
MoleculeChains Sequence LengthOrganismDetailsImage
Beta-2-microglobulin100Homo sapiensMutation(s): 0 
Gene Names: B2MCDABP0092HDCMA22P
UniProt & NIH Common Fund Data Resources
Find proteins for P61769 (Homo sapiens)
Explore P61769 
Go to UniProtKB:  P61769
PHAROS:  P61769
GTEx:  ENSG00000166710 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP61769
Sequence Annotations
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  • Reference Sequence

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Entity ID: 3
MoleculeChains Sequence LengthOrganismDetailsImage
MHC I-peptide11Human immunodeficiency virus 1Mutation(s): 0 
Entity Groups  
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Sequence Annotations
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  • Reference Sequence
Small Molecules
Modified Residues  1 Unique
IDChains TypeFormula2D DiagramParent
MAA
Query on MAA
C
L-PEPTIDE LINKINGC4 H9 N O2ALA
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.65 Å
  • R-Value Free: 0.214 
  • R-Value Work: 0.204 
  • R-Value Observed: 0.205 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 50.55α = 90
b = 80.91β = 90
c = 108.71γ = 90
Software Package:
Software NamePurpose
REFMACrefinement
XDSdata reduction
XDSdata scaling
PHENIXphasing

Structure Validation

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Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
National Institutes of Health/National Human Genome Research Institute (NIH/NHGRI)United States--

Revision History  (Full details and data files)

  • Version 1.0: 2019-10-16
    Type: Initial release
  • Version 1.1: 2019-10-23
    Changes: Data collection, Database references
  • Version 1.2: 2019-12-18
    Changes: Author supporting evidence, Database references
  • Version 1.3: 2020-07-29
    Type: Remediation
    Reason: Carbohydrate remediation
    Changes: Data collection, Structure summary
  • Version 2.0: 2023-03-01
    Changes: Advisory, Data collection, Database references, Non-polymer description, Polymer sequence, Source and taxonomy, Structure summary
  • Version 2.1: 2023-10-25
    Changes: Data collection, Refinement description