title: Crystal structure of the I-domain from the CD11a/CD18 (LFA-1, alpha L beta 2) integrin.
abstract: We report the 1.8-A crystal structure of the CD11a I-domain with bound manganese ion. The CD11a I-domain contains binding sites for intercellular adhesion molecules 1 and 3 and can exist in both low- and high-affinity states. The metal-bound form reported here is likely to represent a high-affinity state. The CD11a I-domain structure reveals a strained hydrophobic ridge adjacent to the bound metal ion that may serve as a ligand-binding surface and is likely to rearrange in the absence of bound metal ion. The CD11a I-domain is homologous to domains found in von Willebrand factor, and mapping of mutations found in types 2a and 2b von Willebrand disease onto this structure allows consideration of the molecular basis of these forms of the disease.
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D002460:Cell Line; D003001:Cloning, Molecular; D003460:Crystallization; D018360:Crystallography, X-Ray; D004926:Escherichia coli; D006801:Humans; D016169:Lymphocyte Function-Associated Antigen-1 / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009154:Mutation; D016133:Polymerase Chain Reaction; D017433:Protein Structure, Secondary; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000302:isolation & purification; D017386:Sequence Homology, Amino Acid; D014842:von Willebrand Diseases / Q000235:genetics; D014841:von Willebrand Factor / Q000737:chemistry / Q000235:genetics
chemical_list: D016169:Lymphocyte Function-Associated Antigen-1; D011994:Recombinant Proteins; D014841:von Willebrand Factor