Crystal structure of mouse H2-M.
H2-M (HLA-DM in humans) resides in an acidic endosomal compartment, where it facilitates the loading of antigenic peptides into the peptide-binding groove of class II MHC. The crystal structure of a soluble form of H2-M has been solved to 3.1 A resolution, revealing a heterodimer with structural similarities to the MHC family of proteins. In contrast to its antigen-presenting cousins, the membrane distal alpha helices of H2-M pack closely together, occluding most of the binding groove except for a single large pocket near the center. The structure of H2-M has several unique features that may play a role in its function as a molecular chaperone and peptide exchange factor.
Fremont
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DH
Center for Immunology, Department of Pathology, Washington University School of Medicine, St. Louis, Missouri 63110, USA. fremont@immunology.wustl.edu
Crawford
F
F
Marrack
P
P
Hendrickson
W A
WA
Kappler
J
J
D000595:Amino Acid Sequence; D000818:Animals; D017124:Conserved Sequence; D018360:Crystallography, X-Ray; D006681:HLA-D Antigens / Q000737:chemistry* / Q000302:isolation & purification / Q000502:physiology; D015395:Histocompatibility Antigens Class I / Q000737:chemistry; D000949:Histocompatibility Antigens Class II / Q000737:chemistry; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D012995:Solubility
C416189:H2-M antigens; D006681:HLA-D Antigens; C084245:HLA-DM antigens; D015395:Histocompatibility Antigens Class I; D000949:Histocompatibility Antigens Class II