Asymmetric framework motion of TCRαβ controls load-dependent peptide discrimination

  1. Ana Cristina Chang-Gonzalez
  2. Robert J Mallis
  3. Matthew J Lang
  4. Ellis L Reinherz
  5. Wonmuk Hwang  Is a corresponding author
  1. Texas A&M University, United States
  2. Dana-Farber Cancer Institute, United States
  3. Vanderbilt University, United States

Abstract

Mechanical force is critical for the interaction between an αβT cell receptor (TCR) and a peptide-bound major histocompatibility complex (pMHC) molecule to initiate productive T-cell activation. However, the underlying mechanism remains unclear. We use all-atom molecular dynamics simulations to examine the A6 TCR bound to HLA-A*02:01 presenting agonist or antagonist peptides under different extensions to simulate the effects of applied load on the complex, elucidating their divergent biological responses. We found that TCR α and β chains move asymmetrically, which impacts the interface with pMHC, in particular the peptide-sensing CDR3 loops. For the wild-type agonist, the complex stabilizes in a load-dependent manner while antagonists destabilize it. Simulations of the Cβ FG-loop deletion, which reduces the catch bond response, and simulations with in silico mutant peptides further support the observed behaviors. The present results highlight the combined role of interdomain motion, fluctuating forces, and interfacial contacts in determining the mechanical response and fine peptide discrimination by a TCR, thereby resolving the conundrum of nearly identical crystal structures of TCRαβ-pMHC agonist and antagonist complexes.

Data availability

The current manuscript is a computational study, so no data have been generated for this manuscript. Sample analysis scripts are available on GitHub: https://github.com/hwm2746/a6tcr_anal_md/tree/main

Article and author information

Author details

  1. Ana Cristina Chang-Gonzalez

    Department of Biomedical Engineering, Texas A&M University, College Station, United States
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-1517-4172
  2. Robert J Mallis

    Laboratory of Immunobio, Dana-Farber Cancer Institute, Boston, United States
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-2087-9468
  3. Matthew J Lang

    Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, United States
    Competing interests
    The authors declare that no competing interests exist.
  4. Ellis L Reinherz

    Laboratory of Immunobio, Dana-Farber Cancer Institute, Boston, United States
    Competing interests
    The authors declare that no competing interests exist.
  5. Wonmuk Hwang

    Department of Biomedical Engineering, Texas A&M University, College Station, United States
    For correspondence
    hwm@tamu.edu
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0001-7514-3186

Funding

US National Institutes of Health (P01AI143565)

  • Robert J Mallis
  • Matthew J Lang
  • Ellis L Reinherz
  • Wonmuk Hwang

US National Institutes of Health (R01AI136301)

  • Matthew J Lang
  • Ellis L Reinherz

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.

Reviewing Editor

  1. Qiang Cui, Boston University, United States

Version history

  1. Received: August 14, 2023
  2. Preprint posted: September 13, 2023 (view preprint)
  3. Accepted: December 21, 2023
  4. Accepted Manuscript published: January 3, 2024 (version 1)
  5. Version of Record published: February 15, 2024 (version 2)

Copyright

© 2024, Chang-Gonzalez et al.

This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.

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  1. Ana Cristina Chang-Gonzalez
  2. Robert J Mallis
  3. Matthew J Lang
  4. Ellis L Reinherz
  5. Wonmuk Hwang
(2024)
Asymmetric framework motion of TCRαβ controls load-dependent peptide discrimination
eLife 13:e91881.
https://doi.org/10.7554/eLife.91881

Share this article

https://doi.org/10.7554/eLife.91881

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