6LHG

Crystal structure of chicken cCD8aa/pBF2*04:01

Summary for 6LHG

• Entry DOI: 10.2210/pdb6lhg/pdb
• Descriptor: MHC class I alpha chain 2, Beta-2-microglobulin, IE8 peptide, ... (5 entities in total)
• Functional Keywords: chicken, complex, bf2*04:01, immune system
• Biological source: Gallus gallus (Chicken); More
• Total number of polymer chains: 10
• Total formula weight: 141099.78

Authors

Liu, Y.J.,Xia, C. (deposition date: 2019-12-08, release date: 2020-12-09, Last modification date: 2024-10-16)

Primary citation

Liu, Y.,Chen, R.,Liang, R.,Sun, B.,Wu, Y.,Zhang, L.,Kaufman, J.,Xia, C.
The Combination of CD8 alpha alpha and Peptide-MHC-I in a Face-to-Face Mode Promotes Chicken gamma delta T Cells Response.
Front Immunol, 11:605085-605085, 2020

PubMed Abstract: The CD8αα homodimer is crucial to both thymic T cell selection and the antigen recognition of cytotoxic T cells. The CD8-pMHC-I interaction can enhance CTL immunity stabilizing the TCR-pMHC-I interaction and optimizing the cross-reactivity and Ag sensitivity of CD8 T cells at various stages of development. To date, only human and mouse CD8-pMHC-I complexes have been determined. Here, we resolved the pBF2*1501 complex and the cCD8αα/pBF2*1501 and cCD8αα/pBF2*0401 complexes in nonmammals for the first time. Remarkably, cCD8αα/pBF2*1501 and the cCD8αα/pBF2*0401 complex both exhibited two binding modes, including an "antibody-like" mode similar to that of the known mammal CD8/pMHC-I complexes and a "face-to-face" mode that has been observed only in chickens to date. Compared to the "antibody-like" mode, the "face-to-face" binding mode changes the binding orientation of the cCD8αα homodimer to pMHC-I, which might facilitate abundant γδT cells to bind diverse peptides presented by limited BF2 alleles in chicken. Moreover, the forces involving in the interaction of cCD8αα/pBF2*1501 and the cCD8αα/pBF2*0401 are different in this two binding model, which might change the strength of the CD8-pMHC-I interaction, amplifying T cell cross-reactivity in chickens. The coreceptor CD8αα of TCR has evolved two peptide-MHC-I binding patterns in chickens, which might enhance the T cell response to major or emerging pathogens, including chicken-derived pathogens that are relevant to human health, such as high-pathogenicity influenza viruses.

PubMed: 33329601
DOI: 10.3389/fimmu.2020.605085

Experimental method

X-RAY DIFFRACTION (2.8 Å)