莱茵衣藻FAB2的原核表达以及不同胁迫条件下的表达模式

摘要

Fatty acid desaturases are enzymes that introduce double bonds into the hydrocarbon chains of fatty acids. The expression of genes for desaturase is very important since it provides the molecular basis for the acclimation of organisms to changing environment. The plastid acyl-ACP desaturase（FAB2） from Chlamydomonas reinhardi is a kind of A9 desaturase, which catalyses the formation of a double bond between the ninth and tenth carbon in the fatty acid chain. In this paper, acyl-ACP desaturase （FAB2） From C. reinhardi was heterologous expressed in Escherichia coli. Homologous annlysis indicated that amino sequence of FAB2 is quite similar to those homologies from plants. The expression levels of FAB2 from C. reinhardi cells which under different temperature and salinity stresses were relatively analysised by using fluorescent quantitative real-time PCR technology. Results showed that the expression quantity of FAB2 during 4℃＋0%NaC1, 25℃ ＋ 1%NaCl were much higer than that of normal situations.%脂肪酸去饱和酶（fattyaciddesaturase）是不饱和脂肪酸合成途径的关键酶，催化脂肪酸链的特定位置脱氢形成双键，其通过引入双键调节脂肪酸不饱和度，以适应周围环境的变化。菜茵衣藻（Chlamydomonasreinhardtii）质体酰基一酰基载体蛋白去饱和酶（plastidacyl—ACPdesaturase，FAB2）在△9位脱氢，催化脂肪酸中第1个双键的形成。本文首先在大肠杆菌中异源表达了FAB2，另外将其氨基酸序列与其他高等植物、微藻、真菌等进行了多序列比对以及系统进化分析，推测其与高等植物亲缘关系更近。利用定量RT-PCR技术研究了衣藻FAB2基因不同胁迫条件下的表达模式，结果表明4℃＋0％NaCl，25℃＋1％NaCl胁迫条件下FAB2基因表达量都有一定程度升高。