TAILIEUCHUNG - Báo cáo khoa học: Coq10, a mitochondrial coenzyme Q binding protein, is required for proper respiration in Schizosaccharomyces pombe

It has been widely accepted that most coenzyme Q (CoQ) exists freely in the mitochondrial membrane as a CoQ pool. However, the recent identifi-cation of a mitochondrial CoQ-binding protein, termed Coq10, in budding yeast has the potential to change our current view of CoQ status in mem-branes. | Coq10 a mitochondrial coenzyme Q binding protein is required for proper respiration in Schizosaccharomyces pombe Tie-Zhong Cui and Makoto Kawamukai Department of Applied Bioscience and Biotechnology Faculty of Life and EnvironmentalScience Shimane University Matsue Japan Keywords coenzyme Q coq10 CoQ-binding protein Schizosaccharomyces pombe ubiquinone Correspondence M. Kawamukai Department of Applied Bioscience and Biotechnology Faculty of Life and Environmental Science Shimane University 1060 Nishikawatsu Matsue 690-8504 Japan Fax 81 852 32 6092 Tel 81 852 32 6587 E-mail kawamuka@ Received 21 August 2008 revised 17 October 2008 accepted 27 November 2008 doi It has been widely accepted that most coenzyme Q CoQ exists freely in the mitochondrial membrane as a CoQ pool. However the recent identification of a mitochondrial CoQ-binding protein termed Coq10 in budding yeast has the potential to change our current view of CoQ status in membranes. Here we studied the counterpart of budding yeast Coq10 also termed Coq10 in fission yeast. Fission yeast coq10 null mutants exhibited a similar but less severe phenotype to CoQ-deficient fission yeast including the requirement for antioxidants for proper growth on minimal medium increased sensitivity to H2O2 high levels of H2S production and a deficiency in respiration. The coq10 null mutant produced nearly normal levels of CoQ10 suggesting that coq10 does not belong to the group of CoQ biosynthetic genes. To elucidate the role of Coq10 we expressed recombinant coq10 in Escherichia coli and found that CoQ8 was present in purified recombinant Coq10. Mutational analysis of 13 conserved residues of Coq10 revealed that two hydrophobic amino acid residues leucine 63 L63 and tryptophan 104 W104 play an important role in Coq10 binding to CoQ. An L63A W104A double mutant of Coq10 exhibited lower CoQ-binding activity than either of the single mutants and was unable to complement the .

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