Synthetic capacity of Arabidopsis phosphatidylinositol synthase 1 expressed in Escherichia coli

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• 作者：Justin ; Anne-Marie ; Kader ; Jean-Claude ; Collin ; Sylvie
• 关键词：Phosphatidylinositol synthase ; Arabidopsis ; Escherichia coli ; Phosphatidylinositol molecular species ; Phospholipid synthesis ; BSA ; bovine serum albumin ; CDP-DAG ; cytidine diphosphodiacylglycerol ; CL ; cardiolipin ; CMP ; cytidine monophosphate ; (d)CDP-DAG ; d
• 刊名：Biochimica et Biophysica Acta (BBA)/Molecular and Cell Biology of Lipids
• 出版年：2003
• 出版时间：October 20, 2003
• 年：2003
• 卷：1634
• 期：1-2
• 页码：52-60
• 全文大小：394 K

文摘

Phosphatidylinositol (PtdIns) synthase 1 from the plant Arabidopsis thaliana has been expressed in Escherichia coli in order to study the synthetic capacities of the enzyme. Analysis of the total fatty acid content of the bacteria shows that PtdIns synthase activity does not have a profound effect on the proportions of the different fatty acids produced, even if the presence of an extra acidic phospholipid leads to a global reduction of the lipid content. A closer analysis carried out on individual phospholipids reveals a global fatty acid composition almost unchanged in the two major bacterial lipids phosphatidylethanolamine (PtdEtn) and phosphatidylglycerol (PtdGro). Phosphatidylinositol has a very unusual composition that shows the ability of the plant enzyme to use CDP-diacylglycerol molecular species absent from plants. We identified the various PtdIns molecular species. They represent a pool of the major molecular species of PtdEtn and PtdGro. These results, together with the determination of the apparent affinity constants of AtPIS1 for myo-inositol and CDP-diacylglycerol, allow us to discuss some of the constraints of PtdIns synthesis in plants in terms of specificity, which will depend on the subcellular localization of the protein.