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cytochrome b558 beta subunit (cytochrome b558 heavy chain, P22 phagocyte B-cytochrome, neutrophil cytochrome B 91 kD polypeptide, CGD91phox, gp91phox, heme binding membrane glycoprotein GP91PHOX, superoxide-generating NADPH oxidase heavy chain subunit, CYBB)

Function: - component of the membrane-bound oxidase of phagocytes that generates superoxide - terminal component of a respiratory chain that transfers single electrons from cytoplasmic NADPH across the plasma membrane to molecular oxygen on the exterior - functions as a voltage-gated proton channel that mediates the H+ currents of resting phagocytes - role in regulation of cellular pH & is blocked by Zn+2 Cofactor: FAD (probable) Structure: - glycosylated - contains 1 ferric oxidoreductase domain Compartment: membrane Pathology: - defects in CYBB are a cause of X-linked chronic granulomatous disease

Related

chronic granulomatous disease CYBB gene mutation

General

glycoprotein protein subunit transmembrane 6 protein

Properties

SIZE: MW = 65 kD entity length = 569 aa COMPARTMENT: cellular membrane MOTIF: cytoplasmic domain {1-7} transmembrane domain {8-28} exoplasmic loop {29-47} transmembrane domain {48-68} cytoplasmic loop {69-101} MOTIF: Iron [Fe]-binding site SITE: 100-100 transmembrane domain {102-122} MOTIF: Iron [Fe]-binding site SITE: 114-114 exoplasmic loop {123-168} MOTIF: N-glycosylation site {N131} N-glycosylation site {N148} transmembrane domain {169-189} cytoplasmic loop {190-199} transmembrane domain {200-220} MOTIF: Iron [Fe]-binding site SITE: 208-208 exoplasmic loop {221-260} MOTIF: Iron [Fe]-binding site SITE: 221-221 N-glycosylation site {N239} transmembrane domain {261-281} cytoplasmic domain {282-569} MOTIF: cofactor-binding site [337-343] COFACTOR-BOUND: flavin adenine dinucleotide

Database Correlations

OMIM correlations UniProt P04839 PFAM correlations

References

  1. Rotrosen D, Yeung CL, Leto TL, Malech HL, Kwong CH. Cytochrome b558: the flavin-binding component of the phagocyte NADPH oxidase. Science. 1992 Jun 5;256(5062):1459-62. PMID: 1318579
  2. Segal AW, Abo A. The biochemical basis of the NADPH oxidase of phagocytes. Trends Biochem Sci. 1993 Feb;18(2):43-7. Review. PMID: 8488557
  3. Pawson T Protein modules and signalling networks Nature 373:573 1995 PMID: 7531822
  4. CYBBbase; CYBB deficiency database http://bioinf.uta.fi/CYBBbase/
  5. GeneReviews https://www.genecards.org/cgi-bin/carddisp.pl?gene=CYBB
  6. UniProt :accession P04839

Component-of

cytochrome b558