Structural Studies of Allelic Diversity of the MHC Class I Homolog MIC-B, a Stress-Inducible Ligand for the Activating Immunoreceptor NKG2D

摘要: MIC-A and MIC-B are distant MHC class I homologs that serve as stress-inducible Ags on epithelial epithelially derived cells. They ligands for the widely expressed activating immunoreceptor NKG2D. To define structural functional consequences of sequence differences between alleles MIC-B, we determined crystal structure one allele human MIC-B. Comparisons two previously reported structures show that, expected, is very similar in to likely interacts with NKG2D an analogous manner. The interdomain flexibility observed structures, a feature unique MIC proteins among homologs, also displayed by relationship intermediate examples structures. Mapping variations onto reveals patterns completely distinct from those classical proteins, number substitutions falling positions affect interactions NKG2D, but other lying binding sites or buried within core proteins.