A conserved energetic footprint underpins recognition of human leukocyte antigen-E by two distinct alpha beta T cell receptors.Sullivan, L.C., Walpole, N.G., Farenc, C., Pietra, G., Sum, M.J.W., Clements, C.S., Lee, E.J., Beddoe, T., Falco, M., Mingari, M.C., Moretta, L., Gras, S., Rossjohn, J., Brooks, A.G.
(2017) J. Biol. Chem. 292: 21149-21158
- PubMed: 28972140
- DOI: 10.1074/jbc.M117.807719
- Primary Citation of Related Structures:
- PubMed Abstract:
αβ T cell receptors (TCRs) interact with peptides bound to the polymorphic major histocompatibility complex class Ia (MHC-Ia) and class II (MHC-II) molecules as well as the essentially monomorphic MHC class Ib (MHC-Ib) molecules. Although there is a ...
αβ T cell receptors (TCRs) interact with peptides bound to the polymorphic major histocompatibility complex class Ia (MHC-Ia) and class II (MHC-II) molecules as well as the essentially monomorphic MHC class Ib (MHC-Ib) molecules. Although there is a large amount of information on how TCRs engage with MHC-Ia and MHC-II, our understanding of TCR/MHC-Ib interactions is very limited. Infection with cytomegalovirus (CMV) can elicit a CD8+ T cell response restricted by the human MHC-Ib molecule human leukocyte antigen (HLA)-E and specific for an epitope from UL40 (VMAPRTLIL), which is characterized by biased TRBV14 gene usage. Here we describe an HLA-E-restricted CD8+ T cell able to recognize an allotypic variant of the UL40 peptide with a modification at position 8 (P8) of the peptide (VMAPRTLVL) that uses the TRBV9 gene segment. We report the structures of a TRBV9+ TCR in complex with the HLA-E molecule presenting the two peptides. Our data revealed that the TRBV9+ TCR adopts a different docking mode and molecular footprint atop HLA-E when compared with the TRBV14+ TCR-HLA-E ternary complex. Additionally, despite their differing V gene segment usage and different docking mechanisms, mutational analyses showed that the TCRs shared a conserved energetic footprint on the HLA-E molecule, focused around the peptide-binding groove. Hence, we provide new insights into how monomorphic MHC molecules interact with T cells.
From the Department of Microbiology and Immunology and Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne 3000, Australia.