7DC6

Giant panda MHC class I complexes

Summary for 7DC6

• Entry DOI: 10.2210/pdb7dc6/pdb
• Descriptor: MHC class I antigen, Beta-2-microglobulin, CCV-NGY9 peptide from Spike protein, ... (4 entities in total)
• Functional Keywords: giant panda, mhc class i, aime-128, immune system
• Biological source: Ailuropoda melanoleuca (Giant panda); More
• Total number of polymer chains: 6
• Total formula weight: 88902.07

Authors

Yuan, H.,Xia, C. (deposition date: 2020-10-23, release date: 2021-06-16, Last modification date: 2024-10-16)

Primary citation

Yuan, H.,Ma, L.,Zhang, L.,Li, X.,Xia, C.
Crystal structure of the giant panda MHC class I complex: First insights into the viral peptide presentation profile in the bear family.
Protein Sci., 29:2468-2481, 2020

PubMed Abstract: The viral cytotoxic T lymphocyte (CTL) epitope peptides presented by classical MHC-I molecules require the assembly of a peptide-MHC-I-β2m (pMHC-I) trimolecular complex for T cell receptor (TCR) recognition, which is the critical activation link for triggering antiviral T cell immunity. Research on T cell immunology in the Ursidae family, especially structural immunology, is still lacking. In this study, the structure of the key trimolecular complex pMHC-I, which binds a peptide from canine distemper virus, was solved for the first time using giant panda as a representative species of Ursidae. The structural characteristics of the giant panda pMHC-I complex (pAime-128), including the unique pockets in the peptide-binding groove (PBG), were analyzed in detail. Comparing the pAime-128 to others in the bear family and extending the comparison to other mammals revealed distinct features. The interaction between MHC-I and β2m, the features of pAime-128 involved in TCR docking and cluster of differentiation 8 (CD8) binding, the anchor sites in the PBG, and the CTL epitopes of potential viruses that infect pandas were clarified. Unique features of pMHC-I viral antigen presentation in the panda were revealed by solving the three-dimensional (3D) structure of pAime-128. The distinct characteristics of pAime-128 indicate an unusual event that emerged during the evolution of the MHC system in the bear family. These results provide a new platform for research on panda CTL immunity and the design of vaccines for application in the bear family.

PubMed: 33078460
DOI: 10.1002/pro.3980

Experimental method

X-RAY DIFFRACTION (2.68 Å)