Yeast and Rat Coq3 and Escherichia coli UbiG Polypeptides Catalyze Both O-Methyltransferase Steps in Coenzyme Q Biosynthesis
作者:Wayne W. Poon、Robert J. Barkovich、Adam Y. Hsu、Adam Frankel、Peter T. Lee、Jennifer N. Shepherd、David C. Myles、Catherine F. Clarke
DOI:10.1074/jbc.274.31.21665
日期:1999.7
Ubiquinone (coenzymeQ or Q) is a lipid that functions in the electron transport chain in the inner mitochondrial membrane of eukaryotes and the plasma membrane of prokaryotes. Q-deficient mutants of Saccharomyces cerevisiae harbor defects in one of eight COQ genes (coq1-coq8) and are unable to grow on nonfermentable carbon sources. The biosynthesis of Q involves two separate O-methylation steps. In
restoration of CoQ biosynthesiscomplex after COQ8 overexpression. The model we propose based on the formation of a multiprotein complex should facilitate a better understanding of CoQ biosynthesis. According to this model, the complex assembly requires the synthesis of a precursor such as HHB by Coq2p that must be recognized by the regulatory protein Coq4p to act as the core component of the complex. The phosphorylation