Structure of a Classical MHC Class I Molecule That Binds "Non-Classical" Ligands.
Hee, C.S., Gao, S., Loll, B., Miller, M.M., Uchanska-Ziegler, B., Daumke, O., Ziegler, A.(2010) PLoS Biol 8: e1000557-e1000557
- PubMed: 21151886 
- DOI: https://doi.org/10.1371/journal.pbio.1000557
- Primary Citation of Related Structures:  
3P73, 3P77 - PubMed Abstract: 
Chicken YF1 genes share a close sequence relationship with classical MHC class I loci but map outside of the core MHC region. To obtain insights into their function, we determined the structure of the YF1*7.1/β(2)-microgloblin complex by X-ray crystallography at 1.3 Å resolution. It exhibits the architecture typical of classical MHC class I molecules but possesses a hydrophobic binding groove that contains a non-peptidic ligand. This finding prompted us to reconstitute YF1*7.1 also with various self-lipids. Seven additional YF1*7.1 structures were solved, but only polyethyleneglycol molecules could be modeled into the electron density within the binding groove. However, an assessment of YF1*7.1 by native isoelectric focusing indicated that the molecules were also able to bind nonself-lipids. The ability of YF1*7.1 to interact with hydrophobic ligands is unprecedented among classical MHC class I proteins and might aid the chicken immune system to recognize a diverse ligand repertoire with a minimal number of MHC class I molecules.
Organizational Affiliation: 
Institut für Immungenetik, Charité-Universitätsmedizin Berlin, Campus Benjamin Franklin, Freie Universität Berlin, Berlin, Germany.