德尔塔还是奥米伽？在原有双键之后，Δ12（ω6）脂肪酸去饱和酶计数 3C。

Delta or Omega? Δ12 (ω6) fatty acid desaturases count 3C after the pre-existing double bond.

机构信息

K.A. Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya Street 35, Moscow, 127276, Russian Federation.

Peoples' Friendship University of Russia (RUDN University), Miklukho-Maklaya Street, Build. 6, Moscow, 117198, Russian Federation.

出版信息

Biochimie. 2020 Dec;179:46-53. doi: 10.1016/j.biochi.2020.09.009. Epub 2020 Sep 16.

DOI:10.1016/j.biochi.2020.09.009

PMID:32946991

Abstract

Fatty acid desaturases (FADs) represent a class of oxygen-dependent enzymes that dehydrogenate C-C bonds in the fatty acids (FAs) producing unsaturated CC double bonds that markedly change the properties of biological membranes. FADs are highly specific towards their acyl substrates, the position and configuration of the introduced double bonds. The double bond positioning of soluble acyl-carrier-protein Δ9-FADs was determined relative to the carboxyl end of a FA. Similar mode was suggested for the acyl-lipid Δ12-FADs (also known as ω6-FADs), however, their exact counting order remain unknown. Here we used monounsaturated odd- (17:1Δ) and even-chain (18:1Δ) FAs to show that acyl-lipid Δ12-FADs of, at least, two cyanobacterial species, Gloeobacter violaceus and Synechocystis sp. strain PCC 6803, use neither end of the fatty acid (Δ or ω) as a counting reference point; but count three carbons toward the methyl end from an existing double bond in the monoene precursors irrespective of a FA chain length.

摘要

脂肪酸去饱和酶（FADs）是一类依赖于氧的酶，能够使脂肪酸（FAs）中的 C-C 键脱氢，生成不饱和的 CC 双键，从而显著改变生物膜的性质。FADs 对其酰基底物具有高度的特异性，包括引入双键的位置和构型。可溶性酰基辅酶 A Δ9-FADs 的双键定位相对于 FA 的羧基端确定。类似的模式也被认为适用于酰基脂质 Δ12-FADs（也称为 ω6-FADs），然而，其确切的计数顺序仍然未知。在这里，我们使用单不饱和奇数（17:1Δ）和偶数链（18:1Δ）FAs 表明，至少两种蓝细菌，Gloeobacter violaceus 和 Synechocystis sp. strain PCC 6803 的酰基脂质 Δ12-FADs 既不使用脂肪酸（Δ 或 ω）的任何一端作为计数参考点；而是从单烯前体中现有的双键开始，不论 FA 链长如何，向甲基端计数三个碳原子。