6BJ8

TCR55 in complex with Pep20/HLA-B35

Summary for 6BJ8

• Entry DOI: 10.2210/pdb6bj8/pdb
• Related: 6BJ2 6BJ3
• Descriptor: HLA class I histocompatibility antigen, B-35 alpha chain, Beta-2-microglobulin, TCR 55 alpha chain, ... (8 entities in total)
• Functional Keywords: agonist, complex, immune system
• Biological source: Homo sapiens (Human); More
• Total number of polymer chains: 5
• Total formula weight: 97822.19

Authors

Jude, K.M.,Sibener, L.V.,Yang, X.,Garcia, K.C. (deposition date: 2017-11-05, release date: 2018-07-25, Last modification date: 2024-11-06)

Primary citation

Sibener, L.V.,Fernandes, R.A.,Kolawole, E.M.,Carbone, C.B.,Liu, F.,McAffee, D.,Birnbaum, M.E.,Yang, X.,Su, L.F.,Yu, W.,Dong, S.,Gee, M.H.,Jude, K.M.,Davis, M.M.,Groves, J.T.,Goddard III, W.A.,Heath, J.R.,Evavold, B.D.,Vale, R.D.,Garcia, K.C.
Isolation of a Structural Mechanism for Uncoupling T Cell Receptor Signaling from Peptide-MHC Binding.
Cell, 174:672-687.e27, 2018

PubMed Abstract: TCR-signaling strength generally correlates with peptide-MHC binding affinity; however, exceptions exist. We find high-affinity, yet non-stimulatory, interactions occur with high frequency in the human T cell repertoire. Here, we studied human TCRs that are refractory to activation by pMHC ligands despite robust binding. Analysis of 3D affinity, 2D dwell time, and crystal structures of stimulatory versus non-stimulatory TCR-pMHC interactions failed to account for their different signaling outcomes. Using yeast pMHC display, we identified peptide agonists of a formerly non-responsive TCR. Single-molecule force measurements demonstrated the emergence of catch bonds in the activating TCR-pMHC interactions, correlating with exclusion of CD45 from the TCR-APC contact site. Molecular dynamics simulations of TCR-pMHC disengagement distinguished agonist from non-agonist ligands based on the acquisition of catch bonds within the TCR-pMHC interface. The isolation of catch bonds as a parameter mediating the coupling of TCR binding and signaling has important implications for TCR and antigen engineering for immunotherapy.

PubMed: 30053426
DOI: 10.1016/j.cell.2018.06.017

Experimental method

X-RAY DIFFRACTION (1.75 Å)