In vitro reconstitution of monogalactosyldiacylglycerol (MGDG) synthase regulation by thioredoxin.
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.
Yamaryo
Yoshiki
Y
Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259-B-14 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8501, Japan.
Motohashi
Ken
K
Takamiya
Ken-ichiro
K
Hisabori
Toru
T
Ohta
Hiroyuki
H
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*
D004220:Disulfides; D010940:Plant Proteins; D011994:Recombinant Proteins; D013879:Thioredoxins; D005700:Galactosyltransferases; C109990:1,2-diacylglycerol 3-beta-galactosyltransferase