Cloning and functional characterisation of a fatty acyl elongase from southern bluefin tuna (Thunnus maccoyii)
Cloning and functional characterisation of a fatty acyl elongase from southern bluefin tuna (Thunnus maccoyii)
复制标题
DOI：
10.1016/j.cbpb.2009.11.002
复制
发表时间：
2010-02-01
影响因子：
2.2
通讯作者：
Schuller, Kathryn A.
中科院分区：
文献类型：
--
作者：
Gregory, Melissa K.;See, Valene H. L.;Schuller, Kathryn A.
长链多不饱和脂肪酸（LCPUFA）如二十碳五烯酸（EPA; 20：5 n-3）和二十二碳六烯酸（DHA; 22：6 n-3）的合成涉及脂肪酰基去饱和酶和延长酶。海洋鱼类南方蓝鳍金枪鱼（SBT）可以在其肉中积累大量的omega-3（n-3）LCPUFA，但它们合成EPA和DHA的能力尚不确定。从SBT肝组织中扩增出一个编码脂肪酰基延伸酶的cDNA，sbtElovl 5。该cDNA包含一个开放阅读框（ORF），编码294个氨基酸。序列比较和系统发育分析显示sbtElovl 5和其他鱼类脂肪酰基延伸酶序列之间具有很高的序列保守性。sbtElovl 5 ORF在酿酒酵母中的异源表达证实其编码能够延伸C-18/20多不饱和脂肪酸（PUFA）底物而不是C-22 PUFA底物的脂肪酰基延伸酶。首次在Elov 15中，研究了自然界中发生的底物竞争。无论底物链长度如何，对n-3 PUFA底物的活性都高于ω-6（n-6）PUFA底物。sbtElovl 5优先伸长18：4 n-3和18：3 n-6，而不是20：5 n-3和20：4 n-6。sbtEIovl 5酶还延长饱和和单不饱和脂肪酸。皇冠版权所有（C）2009由爱思唯尔公司出版。All rights reserved.
The synthesis of long chain polyunsaturated fatty acids (LCPUFA), such as eicosapentaenoic acid (EPA; 20:5n-3) and docosahexaenoic acid (DHA; 22:6n-3), involves fatty acyl desaturase and elongase enzymes. The marine fish species southern bluefin tuna (SBT) can accumulate large quantities of omega-3 (n-3) LCPUFA in its flesh but their capacity to synthesize EPA and DHA is uncertain. A cDNA, sbtElovl5, encoding a putative fatty acyl elongase was amplified from SBT liver tissue. The cDNA included an open reading frame (ORF) encoding 294 amino acids. Sequence comparisons and phylogenetic analyses revealed a high level of sequence conservation between sbtElovl5 and fatty acyl elongase sequences from other fish species. Heterologous expression of the sbtElovl5 ORF in Saccharomyces cerevisiae confirmed that it encoded a fatty acyl elongase capable of elongating C-18/20 polyunsaturated fatty acid (PUFA) substrates, but not C-22 PUFA substrates. For the first time in an Elov15, the substrate competition occurring in nature was investigated. Higher activity towards n-3 PUFA substrates than omega-6 (n-6) PUFA substrates was exhibited, regardless of substrate chain length. The sbtElovl5 preferentially elongated 18:4n-3 and 18:3n-6 rather than 20:5n-3 and 20:4n-6. The sbtEIovl5 enzyme also elongated saturated and monounsaturated fatty acids. Crown Copyright (C) 2009 Published by Elsevier Inc. All rights reserved.