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Lipid Biosynthesis in archaea-Exploring its uniqueness and evolutionary position

古细菌中的脂质生物合成——探索其独特性和进化地位

基本信息

批准号：
15370049
负责人：
NISHINO Tokuzo
金额：
$ 9.92万
依托单位：
Tohoku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2004
项目状态：
已结题

项目摘要

The core structure of membrane lipids of archaea have some unique properties that permit archaea to be distinguished from the others, i.e., bacteria and eukaryotes. (S)-2,3-Di-O-geranylgeranylglyceryl phosphate synthase, which catalyzes the transfer of a geranylgeranyl group from geranylgeranyl diphosphate to (S)-3-O-geranylgeranylglyceryl phosphate, is involved in the biosynthesis of archaeal membrane lipids. Enzymes of the UbiA prenyltransferase family are known to catalyze the transfer of a prenyl group to various acceptors with hydrophobic ring structures in the biosynthesis of respiratory quinones, hemes, chlorophylls, vitamin E, and shikonin. The thermoacidophilic archaeon S.solfataricus was found to encode three homologues of UbiA prenyltransferase in its genome. One of the homologues encoded by SSO0583 was expressed in Escherichia coli, purified, and characterized. Radioassay and mass spectrometry analysis data indicated that the enzyme specifically catalyzes the biosynthesis of (S)-2,3-di-O-geranylgeranylglyceryl phosphate. The fact that the orthologues of the enzyme are encoded in almost all archaeal genomes clearly indicates the importance of their functions. A phylogenetic tree constructed using the amino acid sequences of some typical members of the UbiA prenyltransferase family and their homologues from S.solfataricus suggests that the two other S.solfataricus homologues, excluding the (S)-2,3-di-O-geranylgeranylglyceryl phosphate synthase, are involved in the production of respiratory quinone and heme, respectively. We propose here that archaeal prenyltransferases involved in membrane lipid biosynthesis might be prototypes of the protein family and that archaea might have played an important role in the molecular evolution of prenyltransferases.

古细菌膜脂的核心结构具有一些独特的性质，使古细菌与其他古细菌区分开来，即，细菌和真核生物。(S)-2 3，3-二-O-香叶基香叶基甘油磷酸合酶参与古细菌膜脂的生物合成，催化香叶基香叶基从香叶基香叶基二磷酸转移到（S）-3-O-香叶基香叶基甘油磷酸。已知UbiA异戊烯基转移酶家族的酶在呼吸醌、血红素、叶绿素、维生素E和紫草素的生物合成中催化异戊烯基转移至具有疏水环结构的各种受体。嗜热嗜酸古菌S.solfataricus在其基因组中编码UbiA异戊二烯基转移酶的三个同源物。在大肠杆菌中表达的同源物之一编码的SSO 0583，纯化，并进行了表征。放射性分析和质谱分析数据表明，该酶特异性催化（S）-2，3-二-O-香叶基香叶基甘油磷酸的生物合成。这种酶的直向同源物在几乎所有古细菌基因组中都有编码，这一事实清楚地表明了它们功能的重要性。使用UbiA异戊烯基转移酶家族的一些典型成员的氨基酸序列及其来自S.solfataricus的同源物构建的系统发育树表明，除（S）-2，3-二-O-香叶基香叶基甘油磷酸合酶外，其他两个S.solfataricus同源物分别参与呼吸醌和血红素的产生。我们建议在这里，古细菌的异戊二烯基转移酶参与膜脂生物合成可能是原型的蛋白质家族，古细菌可能发挥了重要作用的异戊二烯基转移酶的分子进化。