A novel Δ9 acyl-lipid desaturase, DesC2, from cyanobacteria acts on fatty acids esterified to the sn-2 position of glycerolipids
A novel Δ9 acyl-lipid desaturase, DesC2, from cyanobacteria acts on fatty acids esterified to the sn-2 position of glycerolipids
复制标题
DOI：
10.1042/bj20060039
复制
发表时间：
2006-09-01
影响因子：
4.1
通讯作者：
Shvaji, Sisinthy
中科院分区：
文献类型：
--
作者：
Chintalapati, Suresh;Shyam Sunder Prakash, Jogadhenu;Shvaji, Sisinthy
酰基脂质去饱和酶是将脂肪酸中的C-C单键转化为C=C双键的酶，所述脂肪酸酯化为膜结合的甘油脂。蓝藻中存在四种酰基脂质去饱和酶，即德萨、Des 13、DesC和DesD，分别作用于脂肪酸的Delta（12）、Delta（15）、Delta（9）和Delta（6）位置。这些酶对结合在甘油酯sn-1位的脂肪酸具有特异性。在本研究中，我们已经克隆了两个推定的Delta（9）去饱和酶基因，命名为desC 1和desC 2，从念珠藻物种。desC 1基因与desC基因高度相似，后者编码作用于sn-1位置的C-18脂肪酸的Delta（9）去饱和酶。desC 2的同源物存在于蓝藻物种的基因组中，其中δ（9）-去饱和脂肪酸被酯化到sn-2位置。在集胞藻PCC 6803中的desC 2基因的异源表达，其中在sn-2位置发现饱和脂肪酸，揭示了DesC 2可以使该脂肪酸在sn-2位置去饱和。这些结果表明，desC 2基因是一个新的Δ（9）酰基脂质去饱和酶的基因，作用于脂肪酸酯化的sn-2位置的甘油酯。
Acyl-lipid desaturases are enzymes that convert a C-C single bond into a C=C double bond in fatty acids that are esterified to membrane-bound glycerolipids. Four types of acyl-lipid desaturase, namely DesA, Des13, DesC, and DesD, acting at the Delta(12), Delta(15), Delta(9), and Delta(6) positions of fatty acids respectively, have been characterized in cyanobacteria. These enzymes are specific for fatty acids bound to the sn-1 position of glycerolipids. In the present study, we have cloned two putative genes for a Delta(9) desaturase, designated desC1 and desC2, from Nostoc species. The desC1 gene is highly similar to the desC gene that encodes a Delta(9) desaturase that acts on C-18 fatty acids at the sn-1 position. Homologues of desC2 are found in genomes of cyanobacterial species in which Delta(9)-desaturated fatty acids are esterified to the sn-2 position. Heterologous expression of the desC2 gene in Synechocystis sp. PCC 6803, in which a saturated fatty acid is found at the sn-2 position, revealed that DesC2 could desaturate this fatty acid at the sn-2 position. These results suggest that the desC2 gene is a novel gene for a Delta(9) acyl-lipid desaturase that acts on fatty acids esterified to the sn-2 position of glycerolipids.