title: The X-linked chronic granulomatous disease gene codes for the beta-chain of cytochrome b-245.
abstract: Chronic granulomatous disease (CGD) is a rare inherited disorder associated with a profound predisposition to infection due to the lack of a microbicidal oxidase system in the phagocytes of these patients. This syndrome is most commonly inherited through a defect on the X chromosome and the only clearly defined component of the oxidase system, the very unusual cytochrome b (b-245), has been shown to be missing from the cells of these patients. This cytochrome is a heterodimer composed of an alpha-chain of relative molecular mass (Mr) 23,000 (23K) and a 76-92K beta-chain; neither are detectable in neutrophils from X-linked CGD subjects. The defective X-CGD gene has recently been cloned by 'reverse genetics' but the protein predicted from the proposed complementary DNA sequence was not identified. We have purified the beta-chain of the cytochrome and sequenced 43 amino acids from the N terminus. Almost complete homology was obtained between this sequence and that of the complementary nucleotides 19-147 of the sequence of the X-CGD gene, originally designated as a non-coding region.
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D003062:Codon; D003573:Cytochrome b Group / Q000235:genetics*; D006105:Granulomatous Disease, Chronic / Q000235:genetics*; D006801:Humans; D008970:Molecular Weight; D014176:Protein Biosynthesis; D012689:Sequence Homology, Nucleic Acid; D014960:X Chromosome
chemical_list: D003062:Codon; D003573:Cytochrome b Group; C035130:cytochrome b245