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http://purl.uniprot.org/citations/10518794http://www.w3.org/1999/02/22-rdf-syntax-ns#typehttp://purl.uniprot.org/core/Journal_Citation
http://purl.uniprot.org/citations/10518794http://www.w3.org/1999/02/22-rdf-syntax-ns#typehttp://purl.uniprot.org/core/Journal_Citation
http://purl.uniprot.org/citations/10518794http://www.w3.org/1999/02/22-rdf-syntax-ns#typehttp://purl.uniprot.org/core/Citation
http://purl.uniprot.org/citations/10518794http://www.w3.org/2000/01/rdf-schema#comment"MGDG synthase, the enzyme that catalyzes the synthesis of the major chloroplast membrane lipid monogalactosyldiacylglycerol (MGDG), is encoded by a multigenic family. We have analyzed the biochemical properties, subcellular localization and membrane topology of a spinach chloroplast MGDG synthase, a representative member of the type A family from Spinacia oleracea (soMGD A), using a recombinant protein that was functionally overexpressed in Escherichia coli and specific polyclonal antibodies. We demonstrated that soMGD A could catalyze the synthesis of both 'prokaryotic' and 'eukaryotic' MGDG molecular species in vitro, with a selectivity for diacylglycerol similar to that of purified chloroplast envelope MGDG synthase activity. Furthermore, soMGD A was shown to be sensitive to chemical reagents (dithiothreitol, N-ethylmaleimide and o-phenanthroline) known to affect MGDG synthesis by the partially purified enzyme, as well as in isolated chloroplast envelope membranes. In spinach chloroplasts, soMGD A was localized by Western blot analysis in the inner envelope membrane. Topological studies demonstrated that soMGD A is a monotopic enzyme, embedded within one leaflet of the inner envelope membrane from spinach chloroplasts, a structure which may involve amphipathic alpha helices. We further demonstrated that in vitro, soMGD A precursor is imported and processed to its correct mature form in intact chloroplasts. These results show that soMGD A corresponds to a mature polypeptide of approximately 45 kDa. In addition, inactivation kinetics after gamma-ray irradiation strongly suggest that both native chloroplast envelope MGDG synthase and recombinant soMGD A have a functional molecular mass of 95-100 kDa, indicating that they are probably active as homodimers made of two 45-kDa subunits. This study suggests that, in spite of the growing evidence that MGDG synthesis is catalyzed by a multigenic family of enzymes, in spinach leaves both prokaryotic and eukaryotic MGDG syntheses could be attributable to a unique dimeric enzyme, provided that diacylglycerol is transported from the outer membrane to the inner membrane of the chloroplast envelope."xsd:string
http://purl.uniprot.org/citations/10518794http://purl.org/dc/terms/identifier"doi:10.1046/j.1432-1327.1999.00801.x"xsd:string
http://purl.uniprot.org/citations/10518794http://purl.org/dc/terms/identifier"doi:10.1046/j.1432-1327.1999.00801.x"xsd:string
http://purl.uniprot.org/citations/10518794http://purl.uniprot.org/core/author"Ohta H."xsd:string
http://purl.uniprot.org/citations/10518794http://purl.uniprot.org/core/author"Ohta H."xsd:string
http://purl.uniprot.org/citations/10518794http://purl.uniprot.org/core/author"Shimojima M."xsd:string
http://purl.uniprot.org/citations/10518794http://purl.uniprot.org/core/author"Shimojima M."xsd:string
http://purl.uniprot.org/citations/10518794http://purl.uniprot.org/core/author"Joyard J."xsd:string
http://purl.uniprot.org/citations/10518794http://purl.uniprot.org/core/author"Joyard J."xsd:string
http://purl.uniprot.org/citations/10518794http://purl.uniprot.org/core/author"Takamiya K."xsd:string
http://purl.uniprot.org/citations/10518794http://purl.uniprot.org/core/author"Takamiya K."xsd:string
http://purl.uniprot.org/citations/10518794http://purl.uniprot.org/core/author"Awai K."xsd:string
http://purl.uniprot.org/citations/10518794http://purl.uniprot.org/core/author"Awai K."xsd:string
http://purl.uniprot.org/citations/10518794http://purl.uniprot.org/core/author"Douce R."xsd:string
http://purl.uniprot.org/citations/10518794http://purl.uniprot.org/core/author"Douce R."xsd:string
http://purl.uniprot.org/citations/10518794http://purl.uniprot.org/core/author"Block M.A."xsd:string
http://purl.uniprot.org/citations/10518794http://purl.uniprot.org/core/author"Block M.A."xsd:string
http://purl.uniprot.org/citations/10518794http://purl.uniprot.org/core/author"Marechal E."xsd:string
http://purl.uniprot.org/citations/10518794http://purl.uniprot.org/core/author"Marechal E."xsd:string
http://purl.uniprot.org/citations/10518794http://purl.uniprot.org/core/author"Miege C."xsd:string
http://purl.uniprot.org/citations/10518794http://purl.uniprot.org/core/author"Miege C."xsd:string
http://purl.uniprot.org/citations/10518794http://purl.uniprot.org/core/date"1999"xsd:gYear
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