In vitro heme O synthesis by the cyoE gene product from Escherichia coli.
The cytochrome bo complex is a heme-copper terminal quinol oxidase in the aerobic respiratory chain of Escherichia coli and contains low spin heme B, high spin heme O and CuB as the redox metal centers in subunit I. Based on site-directed mutagenesis studies on the cyoE gene in the cytochrome bo operon, we have postulated that the cyoE gene encodes a protoheme IX farnesyltransferase (heme O synthase) (Saiki, K., Mogi, T., and Anraku, Y. (1992) Biochem. Biophys. Res. Commun. 189, 1491-1497). The present study demonstrates that the CyoE protein is localized in the cytoplasmic membrane and that the CyoE-overproduced membranes efficiently catalyze a conversion of exogenous ferrous protoheme IX and farnesyl diphosphate to heme O in the presence of divalent cations such as Mg2+ or Ca2+. Thus, the cyoABCDE operon in E. coli encodes not only subunits of the cytochrome bo complex but also heme O synthase that is specifically required for functional expression of the bo-type quinol oxidase. Heme O seems to be an intermediate in heme A biosynthesis.
Saiki
K
K
Department of Plant Sciences, Graduate School of Science, University of Tokyo, Japan.
Mogi
T
T
Ogura
K
K
Anraku
Y
Y
D019883:Alkyl and Aryl Transferases; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D003573:Cytochrome b Group; D003580:Cytochromes / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology / Q000378:metabolism*; D029968:Escherichia coli Proteins; D005294:Ferrochelatase / Q000235:genetics / Q000378:metabolism; D006418:Heme / Q000096:biosynthesis*
D001426:Bacterial Proteins; D003573:Cytochrome b Group; D003580:Cytochromes; D029968:Escherichia coli Proteins; C069808:heme O; D006418:Heme; C017168:cytochrome bo, E coli; D019883:Alkyl and Aryl Transferases; C078356:CyoE protein, Bacteria; C489727:CyoE protein, E coli; D005294:Ferrochelatase