拟南芥磷脂：二酰基甘油酰基转移酶的克隆和功能鉴定。,Plant Physiology

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拟南芥磷脂：二酰基甘油酰基转移酶的克隆和功能鉴定。
Plant Physiology ( IF 6.5 ) Pub Date : 2004-07-13 , DOI: 10.1104/pp.104.044354
Ulf Ståhl ₁ , Anders S Carlsson , Marit Lenman , Anders Dahlqvist , Bangquan Huang , Walentyna Banas , Antoni Banas , Sten Stymne

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最近描述了涉及磷脂：二酰基甘油酰基转移酶（PDAT）的三酰基甘油生物合成的新途径（Dahlqvist A，Stahl U，Lenman M，Banas A，Lee M，Sandager L，Ronne H，Stymne S，[2000] Proc Natl Acad Sci美国97：6487-6492）。在酵母（酿酒酵母）中鉴定出编码PDAT的LRO1基因，并证明与动物卵磷脂：胆固醇酰基转移酶具有同源性。拟南芥基因组数据库的搜索确定了由At5g13640基因编码的蛋白质是与酵母PDAT最接近的同源物（28％氨基酸同一性）。At5g13640的cDNA（AtPDAT基因）在花椰菜花叶病毒启动子后的拟南芥中过表达。过表达者的根和叶的微粒体制剂的PDAT活性与该基因的表达水平相关，因此证明该基因编码PDAT（AtPDAT）。AtPDAT利用不同的磷脂作为酰基供体，并接受从C10到C22的酰基。活性速率高度依赖于具有最高活性的酰基组成，该酰基对于包含几个双键，环氧基或羟基的酰基具有最高活性。该酶利用了磷脂酰胆碱的两个sn-位置，但是对sn-2位置具有3倍的偏好。过量表达AtPDAT的拟南芥植物中的脂肪酸和脂质组成以及每鲜重的脂质含量与野生型无显着差异。来自AtPDAT基因中T-DNA插入突变体的根的微粒体制剂几乎无法检测到将酰基从磷脂转移至添加的二酰基甘油的能力。然而，

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Cloning and functional characterization of a phospholipid:diacylglycerol acyltransferase from Arabidopsis.

A new pathway for triacylglycerol biosynthesis involving a phospholipid:diacylglycerol acyltransferase (PDAT) was recently described (Dahlqvist A, Stahl U, Lenman M, Banas A, Lee M, Sandager L, Ronne H, Stymne S, [2000] Proc Natl Acad Sci USA 97: 6487-6492). The LRO1 gene that encodes the PDAT was identified in yeast (Saccharomyces cerevisiae) and shown to have homology with animal lecithin:cholesterol acyltransferase. A search of the Arabidopsis genome database identified the protein encoded by the At5g13640 gene as the closest homolog to the yeast PDAT (28% amino acid identity). The cDNA of At5g13640 (AtPDAT gene) was overexpressed in Arabidopsis behind the cauliflower mosaic virus promoter. Microsomal preparations of roots and leaves from overexpressers had PDAT activities that correlated with expression levels of the gene, thus demonstrating that this gene encoded PDAT (AtPDAT). The AtPDAT utilized different phospholipids as acyl donor and accepted acyl groups ranging from C10 to C22. The rate of activity was highly dependent on acyl composition with highest activities for acyl groups containing several double bonds, epoxy, or hydroxy groups. The enzyme utilized both sn-positions of phosphatidylcholine but had a 3-fold preference for the sn-2 position. The fatty acid and lipid composition as well as the amounts of lipids per fresh weight in Arabidopsis plants overexpressing AtPDAT were not significantly different from the wild type. Microsomal preparations of roots from a T-DNA insertion mutant in the AtPDAT gene had barely detectable capacity to transfer acyl groups from phospholipids to added diacylglycerols. However, these microsomes were still able to carry out triacylglycerol synthesis by a diacylglycerol:diacylglycerol acyltransferase reaction at the same rate as microsomal preparations from wild type.

更新日期：2019-11-01

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