山杏苹果酸酶基因的克隆与生物信息学分析

Cloning of Malic Enzyme Gene From Prunus armeniaca and its Bioinformatics Analysis

三羧酸转运体系(柠檬酸,苹果酸和丙酮酸)可为脂肪酸生物合成提供原料乙酰辅酶A与还原力NADPH;而苹果酸酶可催化苹果酸发生氧化脱羧而产生NADPH,是调控脂肪酸代谢的重要酶。山杏种子脂肪酸含量丰富、产油率高,是研究植物油脂代谢的良好材料。本研究以山杏为试材,采用RACE克隆和电子拼接相结合的方法,首次从山杏种子中克隆得到苹果酸酶基因(命名为SaME,GenBank上登记号为JX262381),该基因的cDNA编码区全长1923bp、编码640个氨基酸,预测其编码蛋白分子量为70.15kD、等电点为6.38;同时,运用生物信息学方法对SaME基因编码蛋白的理化特性、结构域和亚细胞定位等方面进行预测分析,结果显示,该蛋白定位在细胞的质体膜上,具有苹果酸酶活性,属于NADP-ME超家族。本文对山杏SaME基因的克隆与分析,为进一步探究苹果酸酶对油脂代谢的调控机制奠定了基础。

The tricarboxylic acid transport system is composed of citrate, malate and pyruvate, and its main physi-ological function is to provide the raw materials acetyl-CoA and the reducing power NADPH necessary for the biosynthesis of fatty acids. Malic enzyme, by which malate is converted to pyruvate via the tricarboxylic acid trans-port system with the production of NADPH, is the main regulated enzyme of the fatty acid biosynthesis in the plants. Prunus armeniaca is a kind ofoil woody plant with high oil content and present a high rate ofoil production in the seeds. It is an ideal material to study the mechanism of plant lipid metabolism. In this paper, a gene encoding malic enzyme, named as SaME （JX262381）, was cloned from P. armeniaca by RACE and electronic splicing tech niques. This full-length cDNA contained an open reading frame of 1 923 bp in length, encoding a polypeptide of 640 amino acid residues with a molecular mass of 70.15 kD and a pI of 6.38. And because of the bioinformatics analysis, the ME protein, localized in the plasma membrane, has the activity of malic enzyme, and it belongs to the superfamily of NADP-ME. The analysis of SaME gene in P. armeniaca provides a theoretical basis to further ex-plore ofmalic enzyme regulation in lipid metabolism.