Biosynthesis of archaeal membrane lipids:: Digeranylgeranylglycerophospholipid reductase of the thermoacidophilic Archaeon Thermoplasma acidophilum
Biosynthesis of archaeal membrane lipids:: Digeranylgeranylglycerophospholipid reductase of the thermoacidophilic Archaeon Thermoplasma acidophilum
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DOI：
10.1093/jb/mvj118
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发表时间：
2006-06-01
影响因子：
2.7
通讯作者：
Eguchi, Tadashi
中科院分区：
文献类型：
--
作者：
Nishimura, Yuji;Eguchi, Tadashi
古菌膜脂的基本核心结构是2,3-二-O-植烷基-sn-甘油基磷酸酯（古菌酸），它是由2,3-二-O-香叶基香叶基甘油基还原而成。磷酸盐。在嗜热嗜酸古菌嗜酸热原体的无细胞提取物中检测到膜脂生物合成中关键酶 2,3-二香叶基香叶基甘油磷脂还原酶的还原酶活性。在膜级分中发现了还原活性，并且该活性需要 FAD 和 NADH。通过超速离心和四个色谱步骤从无细胞提取物中纯化还原酶。纯化的酶在大约处显示单条带。 SDS-PAGE 上的分子量为 45 kDa，并催化 2,3-二-O-香叶基香叶基甘油磷酸酯形成古酸。此外，该酶还催化2,3-二-O-香叶基香叶基甘油基磷酸类似物的还原，例如2,3-二-O-植基-sn-甘油基磷酸盐、3-O-(2,3-二-O-植基-sn-甘油-磷酸)-sn-甘油和2,3-二-O-植基-sn-甘油-磷酸乙醇胺。测定了纯化酶的N端20个氨基酸序列，发现其与嗜酸链霉基因组的Ta0516m基因编码的序列相同。本研究清楚地表明2,3-二香叶基香叶基甘油磷脂还原酶是一种膜相关蛋白，并且2,3-二香叶基香叶基甘油磷脂的每个双键的氢化是由单一酶催化的。
The basic core structure of archaeal membrane lipids is 2,3-di-O-phytanyl-sn-glyceryl phosphate (archaetidic acid), which is formed by the reduction of 2,3-di-O-geranylgeranylglyceryl. phosphate. The reductase activity for the key enzyme in membrane lipid biosynthesis, 2,3-digeranylgeranylglycerophospholipid reductase, was detected in a cell free extract of the thermoacidophilic archaeon Thermoplasma acidophilum. The reduction activity was found in the membrane fraction, and FAD and NADH were required for the activity. The reductase was purified from a cell free extract by ultracentrifugation and four chromatographic steps. The purified enzyme showed a single band at ca. 45 kDa on SDS-PAGE, and catalyzed the formation of archaetidic acid from 2,3-di-O-geranylgeranylglyceryl phosphate. Furthermore, the enzyme also catalyzed the reduction of 2,3-di-O-geranylgeranylglyceryl phosphate analogues such as 2,3-di-O-phytyl-sn-glyceryl phosphate, 3-O-(2,3-di-O-phytyl-sn-glycero-phospho)-sn-glycerol and 2,3-di-O-phytyl-sn-glycero-phosphoethanolamine. The N-terminal 20 amino acid sequence of the purified enzyme was determined and was found to be identical to the sequence encoded by the Ta0516m gene of the T. acidophilum genome. The present study clearly demonstrates that 2,3-digeranylgeranylglycerophospholipid reductase is a membrane associated protein and that the hydrogenation of each double bond of 2,3-digeranylgeranylglycerophospholipids is catalyzed by a single enzyme.