Origin of MGDG synthase from chloroplast envelope membranes
Joyard, J.1, Miège, C.1, Maréchal, E.1, Block, M.A.1,Ohta, H.2, Takamiya, K.-I.2, Douce, R.1
1 Laboratoire de Physiologie Cellulaire Végétale, URA 576 (CEA/CNRS/Université Joseph Fourier), Département de Biologie Moléculaire et Structurale,
CEA-Grenoble, 38054 Grenoble-Cedex 9, France
2 Department of Biological Sciences, Faculty of Bioscience and Biotechnology, Tokyo, Institute of Technology, Midori-ku, Yokohama, Kanagawa 226, Japan
Plastid membranes contain galactolipids (monogalactosyldiacylglycerol, or MGDG, and digalactosyldiacylglycerol, or DGDG) as major constituants. MGDG is synthesized in the inner envelope membrane owing to the UDP-galactose:1,2-diacylglycerol 3- -D-galactosyltransferase (MGDG synthase), which transfers a galactose from a water-soluble donor, UDP-galactose (UDP-gal), to a hydrophobic acceptor molecule, diacylglycerol. Shimojima et al. (1997) have cloned a cDNA for MGDG synthase from a cucumber cDNA library and they have demonstrated that the deduced aminoacid sequence has some homology with MurG of Bacillus subtilis and Escherichia coli. We have obtained the homologous cDNA from spinach and have compared the properties of the overexpressed MGDG synthase with those of the partially purified enzyme from spinach chloroplast envelope membranes (Maréchal et al., 1995), especially at the level of the putative UDP-gal binding site. Comparison of sequences from various glycosyltransferases provides some informations on the possible evolutionary origin of the plant enzyme.
Maréchal, E., Miège, C., Block, M.A., Douce, R. and Joyard, J. (1995) The catalytic site of MGDG synthase from spinach chloroplast envelope : A biochemical study of the structure and metal content. J. Biol. Chem., 270, 5714-5722
Shimojima, M., Ohta, H., Iwamatsu, A., Masuda, T., Shioi, Y. and Takamiya, K.-I. (1997) Cloning of the gene of monogalactosyldiacylglycerol synthase and its evolutionary origin. Proc. Natl. Acad. Sci. USA, 94, 333-337
| LOCATION |
DATE |
TIME |
| Lecture Hall I |
Sunday, April 5 |
05:30 pm |