title: The glycoprotein encoded by the X-linked chronic granulomatous disease locus is a component of the neutrophil cytochrome b complex.
abstract: The bacteriocidal capacity of phagocytic cells is impaired in X-linked chronic granulomatous disease (X-CGD), a disorder characterized by the absence of functional plasma-membrane-associated NADPH oxidase. The components of this oxidase system, their correspondence with specific genetic loci, and the primary protein defect in X-CGD remain incompletely defined. We recently reported cloning of the putative X-CGD gene on the basis of DNA linkage. To identify the predicted protein in vivo, antibodies were raised to a synthetic peptide derived from the complementary DNA sequence and to a fusion protein produced in Escherichia coli. In Western blots antisera detect a neutrophil protein of relative molecular mass in 90,000 (90K) that is absent in X-CGD patients. Antisera also react with the larger component of cytochrome b recently purified from neutrophil plasma membranes as a complex of glycosylated 90K and non-glycosylated 22K polypeptides. Based on our identification of the X-CGD protein in vivo, we propose that one of its critical roles is to interact with the 22K species to form a functional cytochrome b complex.
mesh_terms: D000941:Antigens / Q000276:immunology; D003573:Cytochrome b Group / Q000097:blood*; D004247:DNA / Q000235:genetics; D004274:DNA, Recombinant; D006023:Glycoproteins / Q000097:blood / Q000235:genetics*; D006105:Granulomatous Disease, Chronic / Q000097:blood / Q000235:genetics*; D006801:Humans; D007106:Immune Sera / Q000276:immunology; D007118:Immunoassay; D009504:Neutrophils / Q000032:analysis*; D011993:Recombinant Fusion Proteins / Q000276:immunology; D011994:Recombinant Proteins / Q000276:immunology; D014960:X Chromosome
chemical_list: D000941:Antigens; D003573:Cytochrome b Group; D004274:DNA, Recombinant; D006023:Glycoproteins; D007106:Immune Sera; D011993:Recombinant Fusion Proteins; D011994:Recombinant Proteins; D004247:DNA