title: In vitro reconstitution of monogalactosyldiacylglycerol (MGDG) synthase regulation by thioredoxin.
abstract: Monogalactosyldiacylglycerol (MGDG), a major membrane lipid of chloroplasts, is synthesized by MGDG synthase (MGD) localized in chloroplast envelope membranes. We investigated whether MGD activity is regulated in a redox-dependent manner using recombinant cucumber MGD overexpressed in Escherichia coli. We found that MGD activity is reversibly regulated by reduction and oxidation in vitro and that an intramolecular disulfide bond(s) is involved in MGD activation. Because thioredoxin efficiently reduced disulfide bonds to enhance MGD activity in vitro, MGD is potentially an envelope-bound thioredoxin target protein in higher plants.
authors.affiliation: Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259-B-14 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8501, Japan.
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Yamaryo
authors.forename: Ken
authors.initials: K
authors.lastname: Motohashi
authors.forename: Ken-ichiro
authors.initials: K
authors.lastname: Takamiya
authors.forename: Toru
authors.initials: T
authors.lastname: Hisabori
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Ohta
mesh_terms: D002736:Chloroplasts / Q000201:enzymology* / Q000235:genetics; D018553:Cucumis sativus / Q000201:enzymology* / Q000235:genetics; D004220:Disulfides / Q000737:chemistry; D004789:Enzyme Activation; D004926:Escherichia coli; D005700:Galactosyltransferases / Q000737:chemistry* / Q000235:genetics; D007425:Intracellular Membranes / Q000201:enzymology*; D010084:Oxidation-Reduction; D010940:Plant Proteins / Q000737:chemistry* / Q000235:genetics; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics; D013879:Thioredoxins / Q000737:chemistry*
chemical_list: D004220:Disulfides; D010940:Plant Proteins; D011994:Recombinant Proteins; D013879:Thioredoxins; D005700:Galactosyltransferases; C109990:1,2-diacylglycerol 3-beta-galactosyltransferase