Published January 29, 2016 | Version v1
Journal article Open

Toxoplasma gondii peptide ligands open the gate of the HLA class I binding groove

  • 1. University of Oklahoma
  • 2. Technical University of Denmark
  • 3. University at Buffalo
  • 4. La Jolla Institute for Allergy and Immunology
  • 5. University of Chicago

Description

HLA class I presentation of pathogen-derived peptide ligands is essential for CD8+ T-cell recognition of Toxoplasma gondii infected cells. Currently, little data exist pertaining to peptides that are presented after T. gondii infection. Herein we purify HLA-A*02:01 complexes from T. gondii infected cells and characterize the peptide ligands using LCMS. We identify 195 T. gondii encoded ligands originating from both secreted and cytoplasmic proteins. Surprisingly, T. gondii ligands are significantly longer than uninfected host ligands, and these longer pathogen-derived peptides maintain a canonical N-terminal binding core yet exhibit a C-terminal extension of 1-30 amino acids. Structural analysis demonstrates that binding of extended peptides opens the HLA class I F' pocket, allowing the C-terminal extension to protrude through one end of the binding groove. In summary, we demonstrate that unrealized structural flexibility makes MHC class I receptive to parasite-derived ligands that exhibit unique C-terminal peptide extensions.

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Additional details

Identifiers

DOI
10.7554/eLife.12556.001
Other
oai:uchicago.tind.io:9908

Funding

National Institute of Allergy and Infectious Diseases
U01 AI77887
National Institute of Allergy and Infectious Diseases
HHSN272201200010C
National Institute of Allergy and Infectious Diseases
U19 AI062629-05

UChicago Information

Division(s)
Biological Sciences Division
Department(s)
Medicine, Ophthalmology and Visual Science