{"display":true,"structure":{"allele":{"alpha":{"identifier":"ipd-imgt:HLA35266","locus":"hla-a","match_type":"histo:exact","name":"HLA-A*02:01","slug":"hla_a_02_01","species_stem":"hla"},"beta":{}},"assemblies":{"1":{"assembly_name":"1t7y_1","chains":["A","B"],"downloaded_at":"2022-11-09T14:34:50.346234"}},"assembly_count":null,"assigned_chains":{"zag":{"chains":["A"],"match_type":"histo:assign_chains","score":1.0,"sequence":"QENQDGRYSLTYIYTGLSKHVEDVPAFQALGSLNDLQFFRYNSKDRKSQPMGLWRQVEGMEDWKQDSQLQKAREDIFMETLKDIVEYYKDSTGSHVLQGRFGCEIENNRSSGAFWKYYYDGKDYIEFNKEIPAWVPFDPAAQITKQKWEAEPVYVQRAKAYLEEECPATLRKYLKYSKNILDRQDPPSVVVTSHQAPGEKKKLKCLAYDFYPGKIDVHWTRAGEVQEPELRGDVLHNGNGTYQSWVVVAVPPQDTAPYSCHVQHSSLAQPLVVPWEAS"}},"chronology":{"deposition_date":"2004-05-11","deposition_year":2004,"release_date":"2004-12-21","release_year":2004,"revision_date":"2021-10-27","revision_year":2021},"class":"class_i","classical":false,"complex_type":"zag","components":["zag"],"experimental_method":"X-ray diffraction","facets":{},"ligands":[],"locus":"hla-a","manually_edited":{},"missing_residues":[],"page_title":"1T7Y | Non-classical MHC Class I molecule Zinc Alpha-2 Glycoprotein","pdb_code":"1t7y","pdb_title":"Zn-alpha-2-glycoprotein; baculo-zag peg 200, no glycerol","peptide":{"actual_sequence":null,"epitope_info":{},"features":[],"full_sequence":null,"gap_info":{},"gapped_sequence":null,"length":{"numeric":null,"text":null},"unnatural_amino_acids":[]},"publication":{"abstract":"Zn-alpha2-glycoprotein (ZAG) is a 41 kDa soluble protein that is present in most bodily fluids. The previously reported 2.8 A crystal structure of ZAG isolated from human serum demonstrated the structural similarity between ZAG and class I major histocompatibility complex (MHC) molecules and revealed a non-peptidic ligand in the ZAG counterpart of the MHC peptide-binding groove. Here we present crystallographic studies to explore further the nature of the non-peptidic ligand in the ZAG groove. Comparison of the structures of several forms of recombinant ZAG, including a 1.95 A structure derived from ZAG expressed in insect cells, suggests that the non-peptidic ligand in the current structures and in the structure of serum ZAG is a polyethylene glycol (PEG), which is present in the crystallization conditions used. Further support for PEG binding in the ZAG groove is provided by the finding that PEG displaces a fluorophore-tagged fatty acid from the ZAG binding site. From these results we hypothesize that our purified forms of ZAG do not contain a bound endogenous ligand, but that the ZAG groove is capable of binding hydrophobic molecules, which may relate to its function.","bibjson":{"author":[{"initials":"SL","lastname":"Delker","name":"Delker SL"},{"initials":"AP","lastname":"West","name":"West AP"},{"initials":"L","lastname":"McDermott","name":"McDermott L"},{"initials":"MW","lastname":"Kennedy","name":"Kennedy MW"},{"initials":"PJ","lastname":"Bjorkman","name":"Bjorkman PJ"}],"identifier":[{"id":"10.1016/j.jsb.2004.04.009","type":"doi"},{"id":"15477100","type":"pubmed"}],"issue":["2"],"journal":{"iso_abbreviation":"J. Struct. Biol.","name":""},"pages":["205-13"],"title":"Crystallographic studies of ligand binding by Zn-alpha2-glycoprotein.","type":"article","url":"https://www.sciencedirect.com/science/article/abs/pii/S1047847704001029","volume":["148"],"year":[2004]},"in_pmc":"N","in_pmce":"N","open_access":"N"},"resolution":"2.80","same_as":{"pdbe":{"url":"https://www.ebi.ac.uk/pdbe/entry/pdb/1t7y"},"rcsb":{"url":"https://www.rcsb.org/structure/1t7y"}},"species":{"common_name":"Human","match_type":"histo:assign_species","scientific_name":"Homo sapiens","slug":"homo_sapiens"},"tcr":null,"title":"Non-classical MHC Class I molecule Zinc Alpha-2 Glycoprotein at 2.80Å resolution","unique_chain_count":1}}