Isolation and characterization of genes from the marine microalga Pavlova salina encoding three front-end desaturases involved in docosahexaenoic acid biosynthesis
Isolation and characterization of genes from the marine microalga Pavlova salina encoding three front-end desaturases involved in docosahexaenoic acid biosynthesis
复制标题
DOI：
10.1016/j.phytochem.2006.12.016
复制
发表时间：
2007-03-01
期刊：
影响因子：
3.8
通讯作者：
Singh, Surinder P.
中科院分区：
文献类型：
--
作者：
Zhou, Xue-Rong;Robert, Stanley S.;Singh, Surinder P.
海洋微藻巴甫洛瓦盐藻产生的脂肪含有大约50%的omega-3长链多不饱和脂肪酸(LC-PUFA)，如二十二碳六烯酸(DHA)和二十碳五烯酸(EPA)。从盐藻中分离到三个cDNA序列，分别命名为PsD4Des、PsD5Des、PsD8Des，它们分别编码具有Delta 4、Delta 5和Delta 8特异性的3个前端脱饱和酶。Southern分析表明，盐藻基因组中含有所有三个前端脂肪酸去饱和酶基因的单拷贝。当在三种不同的温度下生长时，脂肪酸图谱分析表明，盐藻的去饱和转化效率超过95%。实时荧光定量聚合酶链式反应显示，在正常生长条件下，PsD8Des的表达水平高于其他两个基因，而PsD5Des的表达水平最低。这三个基因的氨基酸序列都包含三个保守的组氨酸盒和一个细胞色素b(5)结构域。序列比对表明，这三个基因与其他微藻和真菌中相应的脱饱和酶同源。这三个导致LC-PUFA合成的前端去饱和酶的预测活性在酵母和高等植物中也得到了证实。皇冠版权所有(C)2007由爱思唯尔有限公司出版。保留所有权利。
The marine microalga Pavlova salina produces lipids containing approximately 50% omega-3 long chain polyunsaturated fatty acids (LC-PUFA) such as docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). Three cDNA sequences, designated PsD4Des, PsD5Des, PsD8Des, were isolated from P. salina and shown to encode three front-end desaturases with Delta 4, Delta 5 and Delta 8 specificity, respectively. Southern analysis indicated that the P. salina genome contained single copies of all three front-end fatty acid desaturase genes. When grown at three different temperatures, analysis of fatty acid profiles indicated P. salina desaturation conversions occurred with greater than 95% efficiency. Real-Time PCR revealed that expression of PsD8Des was higher than for the other two genes under normal growth conditions, while PsD5Des had the lowest expression level. The deduced amino acid sequences from all three genes contained three conserved histidine boxes and a cytochrome b(5) domain. Sequence alignment showed that the three genes were homologous to corresponding desaturases from other microalgae and fungi. The predicted activities of these three front-end desaturases leading to the synthesis of LC-PUFA were also confirmed in yeast and in higher plants. Crown Copyright (c) 2007 Published by Elsevier Ltd. All rights reserved.