title: Characterization and physiological role of two types of chloroplastic fructose-1,6-bisphosphatases in Euglena gracilis.
abstract: The chloroplastic fructose-1,6-bisphosphatase (FBPase) is a late-limiting enzyme in the Calvin cycle. In the present study, we isolated and characterized the cDNAs encoding two types of chloroplastic FBPase isoforms (EgFBPaseI and II) from Euglena gracilis. The Km values of recombinant EgFBPaseI and EgFBPaseII for fructose 1,6-bisphosphate (Fru 1,6-P2) were 165 ± 17 and 2200 ± 200 μM, respectively. The activity of EgFBPaseI was inhibited by 1mM H2O2 and recovered when incubated with DTT. The activity of EgFBPaseII was resistant to concentrations of H2O2 up to 1mM, which was distinct from those of EgFBPaseI and spinach chloroplastic FBPase. The suppression of EgFBPaseI gene expression by gene silencing markedly decreased photosynthetic activity and inhibited cell growth. The results of the present study clearly demonstrated that EgFBPaseI played a critical role in photosynthesis in Euglena chloroplasts.
authors.affiliation: Department of Advanced Bioscience, Faculty of Agriculture, Kinki University, 3327-204 Nakamachi, Nara 631-8505, Japan; Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Chiyoda-ku, Tokyo 102-0076, Japan.
authors.forename: Takahisa
authors.initials: T
authors.lastname: Ogawa
authors.affiliation: Department of Advanced Bioscience, Faculty of Agriculture, Kinki University, 3327-204 Nakamachi, Nara 631-8505, Japan; Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Chiyoda-ku, Tokyo 102-0076, Japan.
authors.forename: Ayako
authors.initials: A
authors.lastname: Kimura
authors.affiliation: Department of Advanced Bioscience, Faculty of Agriculture, Kinki University, 3327-204 Nakamachi, Nara 631-8505, Japan; Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Chiyoda-ku, Tokyo 102-0076, Japan.
authors.forename: Harumi
authors.initials: H
authors.lastname: Sakuyama
authors.affiliation: Department of Advanced Bioscience, Faculty of Agriculture, Kinki University, 3327-204 Nakamachi, Nara 631-8505, Japan; Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Chiyoda-ku, Tokyo 102-0076, Japan. Electronic address: tamoi@nara.kindai.ac.jp.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Tamoi
authors.affiliation: Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Chiyoda-ku, Tokyo 102-0076, Japan; Faculty of Life and Environmental Science, Shimane University, 1060 Nishikawatsu, Matsue, Shimane 690-8504, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Ishikawa
authors.affiliation: Department of Advanced Bioscience, Faculty of Agriculture, Kinki University, 3327-204 Nakamachi, Nara 631-8505, Japan; Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Chiyoda-ku, Tokyo 102-0076, Japan.
authors.forename: Shigeru
authors.initials: S
authors.lastname: Shigeoka
mesh_terms: D000595:Amino Acid Sequence; D002736:Chloroplasts / Q000201:enzymology*; D005056:Euglena gracilis / Q000201:enzymology*; D006597:Fructose-Bisphosphatase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D010802:Phylogeny; D034622:RNA Interference; D017386:Sequence Homology, Amino Acid
chemical_list: D006597:Fructose-Bisphosphatase
keywords: Euglena gracilis; Fructose-1,6-bisphosphatase; Photosynthesis