7EDO

First insight into marsupial MHC I peptide presentation: immune features of lower mammals paralleled with bats

Summary for 7EDO

• Entry DOI: 10.2210/pdb7edo/pdb
• Descriptor: MHC class I antigen, Beta-2-microglobulin, CYS-ASN-VAL-THR-LEU-ASN-TYR-PRO, ... (5 entities in total)
• Functional Keywords: mhc class i, immune system
• Biological source: Trichosurus vulpecula (Brush-tailed possum); More
• Total number of polymer chains: 6
• Total formula weight: 107136.74

Authors

Wang, P.Y.,Yue, C.,Lu, D.,Liu, K.F.,Liu, S.,Yao, S.J.,Chai, Y.,Qi, J.X.,Lou, Y.L.,Sun, Z.Y.,Gao, G.F.,Liu, W.J. (deposition date: 2021-03-16, release date: 2021-08-11, Last modification date: 2024-10-23)

Primary citation

Wang, P.,Yue, C.,Liu, K.,Lu, D.,Liu, S.,Yao, S.,Li, X.,Su, X.,Ren, K.,Chai, Y.,Qi, J.,Zhao, Y.,Lou, Y.,Sun, Z.,Gao, G.F.,Liu, W.J.
Peptide Presentations of Marsupial MHC Class I Visualize Immune Features of Lower Mammals Paralleled with Bats.
J Immunol., 207:2167-2178, 2021

PubMed Abstract: Marsupials are one of three major mammalian lineages that include the placental eutherians and the egg-laying monotremes. The marsupial brushtail possum is an important protected species in the Australian forest ecosystem. Molecules encoded by the MHC genes are essential mediators of adaptive immune responses in virus-host interactions. Yet, nothing is known about the peptide presentation features of any marsupial MHC class I (MHC I). This study identified a series of possum MHC I Trvu-UB*01:01 binding peptides derived from wobbly possum disease virus (WPDV), a lethal virus of both captive and feral possum populations, and unveiled the structure of marsupial peptide/MHC I complex. Notably, we found the two brushtail possum-specific insertions, the 3-aa IleGluArg and 1-aa Arg insertions are located in the Trvu-UB*01:01 peptide binding groove (PBG). The 3-aa insertion plays a pivotal role in maintaining the stability of the N terminus of Trvu-UB*01:01 PBG. This aspect of marsupial PBG is unexpectedly similar to the bat MHC I Ptal-N*01:01 and is shared with lower vertebrates from elasmobranch to monotreme, indicating an evolution hotspot that may have emerged from the pathogen-host interactions. Residue Arg insertion, located in the α2 helix, is available for TCR recognition, and it has a particular influence on promoting the anchoring of peptide WPDV-12. These findings add significantly to our understanding of adaptive immunity in marsupials and its evolution in vertebrates. Our findings have the potential to impact the conservation of the protected species brushtail possum and other marsupial species.

PubMed: 34535575
DOI: 10.4049/jimmunol.2100350

Experimental method

X-RAY DIFFRACTION (2.7 Å)