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eng
Author
Mei Zhang Department of Applied Bioscience and Biotechnology, Faculty of Life and Environmental Science, Shimane University, Japan
Jun Luo Department of Applied Bioscience and Biotechnology, Faculty of Life and Environmental Science, Shimane University, Japan
Ogiyama, Yuki Department of Applied Bioscience and Biotechnology, Faculty of Life and Environmental Science, Shimane University, Japan
Saiki, Ryoichi Department of Applied Bioscience and Biotechnology, Faculty of Life and Environmental Science, Shimane University, Japan
Description
Ubiquinone is an essential factor for the electron transfer system and is also a known lipid antioxidant. The length of the ubiquinone isoprenoid side‐chain differs amongst living organisms, with six isoprene units in the budding yeast Saccharomyces cerevisiae, eight units in Escherichia coli and 10 units in the fission yeast Schizosaccharomyces pombe and in humans. The length of the ubiquinone isoprenoid is determined by the product generated by polyprenyl diphosphate synthases (poly‐PDSs), which are classified into homodimer (i.e. octa‐PDS IspB in E. coli) and heterotetramer [i.e. deca‐PDSs Dps1 and D‐less polyprenyl diphosphate synthase (Dlp1) in Sc. pombe and in humans] types. In this study, we characterized the hexa‐PDS (Coq1) of S. cerevisiae to identify whether this enzyme was a homodimer (as in bacteria) or a heteromer (as in fission yeast). When COQ1 was expressed in an E. coli ispB disruptant, only hexa‐PDS activity and ubiquinone‐6 were detected, indicating that the expression of Coq1 alone results in bacterial enzyme‐like functionality. However, when expressed in fission yeast Δdps1 and Δdlp1 strains, COQ1 restored growth on minimal medium in the Δdlp1 but not Δdps1 strain. Intriguingly, ubiquinone‐9 and ubiquinone‐10, but not ubiquinone‐6, were identified and deca‐PDS activity was detected in the COQ1‐expressing Δdlp1 strain. No enzymatic activity or ubiquinone was detected in the COQ1‐expressing Δdps1 strain. These results indicate that Coq1 partners with Dps1, but not with Dlp1, to be functional in fission yeast. Binding of Coq1 and Dps1 was demonstrated by coimmunoprecipitation, and the formation of a tetramer consisting of Coq1 and Dps1 was detected in Sc. pombe. Thus, Coq1 is functional when expressed alone in E. coli and in budding yeast, but is only functional as a partner with Dps1 in fission yeast. This unusual observation indicates that different folding processes or protein modifications in budding yeast/E. coli versus those in fission yeast might affect the formation of an active enzyme. These results provide important insights into the process of how PDSs have evolved from homo‐ to hetero‐types.
Subject
coenzyme Q
COQ1
isoprenoid
polyprenyl diphosphate synthase
ubiquinone
Journal Title
The FEBS Journal
Volume
275
Issue
14
Start Page
3653
End Page
3668
Published Date
2008-07-03
DOI
Publisher
Federation of European Biochemical Societies
NII Type
Journal Article
Format
PDF
Text Version
著者版
OAI-PMH Set
Faculty of Life and Environmental Science
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