2,3-Dimethyl-6-geranylgeranyl-1,4-benzoquinol

• 分子结构分类: 有机化合物 - 脂质和类脂质分子 - 异戊烯醇脂质
• 英文名称: 2,3-Dimethyl-6-geranylgeranyl-1,4-benzoquinol
• 英文别名: 2,3-dimethyl-5-[(2E,6E,10E)-3,7,11,15-tetramethylhexadeca-2,6,10,14-tetraenyl]benzene-1,4-diol
• 化学式: C₂₈H₄₂O₂
• 分子量: 410.64
• InChiKey: QFMVWSPTQOCGTB-TUZVQDLTSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  8.8
• 重原子数：
  30
• 可旋转键数：
  11
• 环数：
  1.0
• sp3杂化的碳原子比例：
  0.5
• 拓扑面积：
  40.5
• 氢给体数：
  2
• 氢受体数：
  2

反应信息

• 作为反应物：
  描述：

  2,3-Dimethyl-6-geranylgeranyl-1,4-benzoquinol 在 tocopherol cyclase from spheroplasts of Anabaena variabilis 作用下， 以 丙酮 为溶剂， 以83%的产率得到B-生育三烯醇
  参考文献：
  名称：

  The substrate specificity of tocopherol cyclase

  摘要：

  The substrate specificity of the enzyme tocopherol cyclase from the blue-green algae Anabaena variabilis (Cyanobacteria) was investigated with 11 substrate analogues revealing the significance of three major recognition sites: (i) the OH group at C(1) of the hydroquinone, (ii) the (E) configuration of the double bond, and (iii) the length of the lipophilic side chain. Experiments with two affinity matrices suggest that substrates approach the enzyme's active site with the hydrophobic tail. Copyright (C) 1996 Elsevier Science Ltd

  DOI：

  10.1016/0968-0896(96)00125-3
• 作为产物：
  描述：

  B-生育三烯醇 生成 2,3-Dimethyl-6-geranylgeranyl-1,4-benzoquinol
  参考文献：
  名称：

  Isolation of an Arabidopsis mutant lacking vitamin E and identification of a cyclase essential for all tocopherol biosynthesis

  摘要：

  生育酚（维生素E）是一种植物叶绿体脂质，被认为参与响应氧化应激。通过使用基于薄层色谱的筛选方法，从拟南芥（Arabidopsis thaliana）中分离出一个缺乏生育酚的突变体（vte1）。突变体植物缺乏所有四种生育酚形式，并且缺乏生育酚环化酶活性。通过遗传图谱分析vte1和基因组学方法，鉴定了ORF At4g32770作为生育酚环化酶的候选基因。在vte1中，At4g32770含有一个剪切位点突变，并且相应的mRNA表达减少。在大肠杆菌中表达VTE1导致产生具有高生育酚环化酶和生育三烯酚环化酶活性的蛋白质。VTE1序列与已知功能基因没有相似性，但与最近基于蔗糖转运缺陷1玉米突变体（sxd1）的可用性而分离出的SXD1基因相似。在最适生长条件下，vte1突变体的生长、叶绿素含量和光合量子产率与野生型相似。因此，生育酚的缺失对光合作用或植物生存力没有大的影响，表明其他抗氧化剂可以弥补生育酚的损失。在光氧化应激期间，与野生型相比，vte1的叶绿素含量和光合量子产率略有降低，表明生育酚在维持高光压力下的最佳光合速率方面可能发挥了潜在作用。

  DOI：

  10.1073/pnas.182330899

文献信息

• Highly Divergent Methyltransferases Catalyze a Conserved Reaction in Tocopherol and Plastoquinone Synthesis in Cyanobacteria and Photosynthetic Eukaryotes
  作者：Z. Cheng

  DOI：10.1105/tpc.013656

  日期：2003.10.1

  Tocopherols are lipid-soluble compounds synthesized only by photosynthetic eukaryotes and oxygenic cyanobacteria. The pathway and enzymes for tocopherol synthesis are homologous in cyanobacteria and plants except for 2-methyl-6-phytyl-1,4-benzoquinone/2-methyl-6-solanyl-1,4-benzoquinone methyltransferase (MPBQ/MSBQ MT), which catalyzes a key methylation step in both tocopherol and plastoquinone (PQ) synthesis. Using a combined genomic, genetic, and biochemical approach, we isolated and characterized the VTE3 (vitamin E defective) locus, which encodes MPBQ/MSBQ MT in Arabidopsis. The phenotypes of vte3 mutants are consistent with the disruption of MPBQ/MSBQ MT activity to varying extents. The ethyl methanesulfonate–derived vte3-1 allele alters tocopherol composition but has little impact on PQ levels, whereas the null vte3-2 allele is deficient in PQ and α- and γ-tocopherols. In vitro enzyme assays confirmed that VTE3 is the plant functional equivalent of the previously characterized MPBQ/MSBQ MT (Sll0418) from Synechocystis sp PCC6803, although the two proteins are highly divergent in primary sequence. Sll0418 orthologs are present in all fully sequenced cyanobacterial genomes, Chlamydomonas reinhardtii, and the diatom Thalassiosira pseudonana but absent from vascular and nonvascular plant databases. VTE3 orthologs are present in all vascular and nonvascular plant databases and in C. reinhardtii but absent from cyanobacterial genomes. Intriguingly, the only prokaryotic genomes that contain VTE3-like sequences are those of two species of archea, suggesting that, in contrast to all other enzymes of the plant tocopherol pathway, the evolutionary origin of VTE3 may have been archeal rather than cyanobacterial. In vivo analyses of vte3 mutants and the corresponding homozygous Synechocystis sp PCC6803 sll0418::aphII mutant revealed important differences in enzyme redundancy, the regulation of tocopherol synthesis, and the integration of tocopherol and PQ biosynthesis in cyanobacteria and plants.

  chocystis PCC6800的基因组分析表明，VTE3编码的MPBQ/MSBQ MT在拟南芥中具有多种功能。vte3突变体的表型与MPBQ/MSBQ MT活性在不同程度上的破坏相一致。甲基磺酸乙酯衍生的vte3-1等位基因改变了生育酚的组成，但对PQ水平的影响不大，而无效的vte3-2等位基因缺乏PQ和α-生育酚和γ-生育酚。体外酶分析证实，VTE3是植物功能等同于先前从Synechocystis sp PCC6803中鉴定的MPBQ/MSBQ MT（Sll0418），尽管这两种蛋白质在主要序列上差异很大。Sll0418同源物存在于所有完全测序的蓝藻基因组、Chlamydomonas reinhardtii和硅藻Thalassiosira pseudonana中，但不存在于维管植物和非维管植物数据库中。VTE3同源物存在于所有维管植物和非维管植物数据库以及C. reinhardtii中，但不存在于蓝藻基因组中。有趣的是，唯一含有VTE3样序列的原核生物基因组是两种古细菌的基因组，这表明与植物生育酚途径的所有其他酶相反，VTE3的进化起源可能是古细菌而不是蓝藻
• Isolation of an <i>Arabidopsis</i> mutant lacking vitamin E and identification of a cyclase essential for all tocopherol biosynthesis
  作者：Svetlana Porfirova、Eveline Bergmüller、Susanne Tropf、Rainer Lemke、Peter Dörmann

  DOI：10.1073/pnas.182330899

  日期：2002.9.17

  Tocopherol (vitamin E) is a plant chloroplast lipid presumed to be involved in the response to oxidative stress. A tocopherol-deficient mutant ( vte1 ) was isolated from Arabidopsis thaliana by using a TLC-based screening approach. Mutant plants lacked all four tocopherol forms and were deficient in tocopherol cyclase activity. Genetic mapping of vte1 and a genomics-based approach led to the identification of the ORF At4g32770 as a candidate gene for tocopherol cyclase. In vte1 , At4g32770 contains a splicing site mutation and the corresponding mRNA expression is reduced. Expression of VTE1 in Escherichia coli resulted in the production of a protein with high tocopherol cyclase and tocotrienol cyclase activity. The VTE1 sequence shows no similarities to genes with known function, but is similar to that of SXD1 , a gene that was recently isolated based on the availability of the sucrose export defective1 maize mutant ( sxd1 ). Growth of the vte1 mutant, chlorophyll content, and photosynthetic quantum yield were similar to wild type under optimal growth conditions. Therefore, absence of tocopherol has no large impact on photosynthesis or plant viability, suggesting that other antioxidants can compensate for the loss of tocopherol. During photo-oxidative stress, chlorophyll content and photosynthetic quantum yield were slightly reduced in vte1 as compared with wild type indicating a potential role for tocopherol in maintaining an optimal photosynthesis rate under high-light stress.

  生育酚（维生素E）是一种植物叶绿体脂质，被认为参与响应氧化应激。通过使用基于薄层色谱的筛选方法，从拟南芥（Arabidopsis thaliana）中分离出一个缺乏生育酚的突变体（vte1）。突变体植物缺乏所有四种生育酚形式，并且缺乏生育酚环化酶活性。通过遗传图谱分析vte1和基因组学方法，鉴定了ORF At4g32770作为生育酚环化酶的候选基因。在vte1中，At4g32770含有一个剪切位点突变，并且相应的mRNA表达减少。在大肠杆菌中表达VTE1导致产生具有高生育酚环化酶和生育三烯酚环化酶活性的蛋白质。VTE1序列与已知功能基因没有相似性，但与最近基于蔗糖转运缺陷1玉米突变体（sxd1）的可用性而分离出的SXD1基因相似。在最适生长条件下，vte1突变体的生长、叶绿素含量和光合量子产率与野生型相似。因此，生育酚的缺失对光合作用或植物生存力没有大的影响，表明其他抗氧化剂可以弥补生育酚的损失。在光氧化应激期间，与野生型相比，vte1的叶绿素含量和光合量子产率略有降低，表明生育酚在维持高光压力下的最佳光合速率方面可能发挥了潜在作用。
• Current Opinions on the Functions of Tocopherol Based on the Genetic Manipulation of Tocopherol Biosynthesis in Plants
  作者：Yin Li、Zinan Wang、Xiaofen Sun、Kexuan Tang

  DOI：10.1111/j.1744-7909.2008.00689.x

  日期：2008.9

  Abstract As a member of an important group of lipid soluble antioxidants, tocopherols play a paramount role in the daily diet of humans and animals. Recently, genes required for tocochromanol biosynthesis pathway have been identified and cloned with the help of genomics‐based approaches and molecular manipulation in the model organisms: Arabidopsis thaliana and Synechocystis sp. PCC 6803. At the basis of these foundations, genetic manipulation of tocochromanol biosynthesis pathway can give rise to strategies that enhance the level of tocochromanol content or convert the constitution of tocochromanol. In addition, genetic manipulations of the tocochromanol biosynthesis pathway provide help for the study of the function of tocopherol in plant systems. The present article summarizes recent advances and pays special attention to the functions of tocopherol in plants. The roles of tocopherol in the network of reactive oxygen species, antioxidants and phytohormones to maintain redox homeostasis and the functions of tocopherol as a signal molecule in chloroplast‐to‐nucleus signaling to regulate carbohydrate metabolism are also discussed.
• The substrate specificity of tocopherol cyclase
  作者：Achim Stocker、Heinz Fretz、Haroun Frick、August Rüttimann、Wolf-Dietrich Woggon

  DOI：10.1016/0968-0896(96)00125-3

  日期：1996.7

  The substrate specificity of the enzyme tocopherol cyclase from the blue-green algae Anabaena variabilis (Cyanobacteria) was investigated with 11 substrate analogues revealing the significance of three major recognition sites: (i) the OH group at C(1) of the hydroquinone, (ii) the (E) configuration of the double bond, and (iii) the length of the lipophilic side chain. Experiments with two affinity matrices suggest that substrates approach the enzyme's active site with the hydrophobic tail. Copyright (C) 1996 Elsevier Science Ltd
• Characterization of Tocopherol Cyclases from Higher Plants and Cyanobacteria. Evolutionary Implications for Tocopherol Synthesis and Function
  作者：Scott E. Sattler、Edgar B. Cahoon、Sean J. Coughlan、Dean DellaPenna

  DOI：10.1104/pp.103.024257

  日期：2003.8.1

  Tocopherols are lipophilic antioxidants synthesized exclusively by photosynthetic organisms and collectively constitute vitamin E, an essential nutrient for both humans and animals. Tocopherol cyclase (TC) catalyzes the conversion of various phytyl quinol pathway intermediates to their corresponding tocopherols through the formation of the chromanol ring. Herein, the molecular and biochemical characterization of TCs from Arabidopsis (VTE1 [VITAMIN E 1]), Zea mays (SXD1 [Sucrose Export Deficient 1]) and Synechocystis sp. PCC6803 (slr1737) are described. Mutations in the VTE1, SXD1, or slr1737 genes resulted in both tocopherol deficiency and the accumulation of 2,3-dimethyl-6-phytyl-1,4-benzoquinone (DMPBQ), a TC substrate. Recombinant SXD1 and VTE1 proteins are able to convert DMPBQ to γ-tocopherol in vitro. In addition, expression of maize SXD1 in a Synechocystis sp. PCC6803 slr1737 knockout mutant restored tocopherol synthesis, indicating that TC activity is evolutionarily conserved between plants and cyanobacteria. Sequence analysis identified a highly conserved 30-amino acid C-terminal domain in plant TCs that is absent from cyanobacterial orthologs. vte1-2 causes a truncation within this C-terminal domain, and the resulting mutant phenotype suggests that this domain is necessary for TC activity in plants. The defective export of Suc in sxd1 suggests that in addition to presumed antioxidant activities, tocopherols or tocopherol breakdown products also function as signal transduction molecules, or, alternatively, the DMPBQ that accumulates in sxd1 disrupts signaling required for efficient Suc export in maize.

  生物合成的脂溶性抗氧化剂生育酚仅由光合生物合成，共同构成维生素E，是人类和动物的必需营养素。生育酚环化酶（TC）通过形成色酚环催化各种植物醌途径中间体的转化为相应的生育酚。本文描述了来自拟南芥（VTE1 [维生素E 1]）、玉米（SXD1 [蔗糖导出缺陷1]）和Synechocystis sp. PCC6803（slr1737）的TC的分子和生化特性。VTE1、SXD1或slr1737基因的突变导致生育酚缺乏和2,3-二甲基-6-植酰基-1,4-苯醌（DMPBQ）的积累，这是TC底物。重组的SXD1和VTE1蛋白能够在体外将DMPBQ转化为γ-生育酚。此外，将玉米SXD1在Synechocystis sp. PCC6803 slr1737敲除突变体中表达可恢复生育酚合成，表明植物和蓝细菌之间的TC活性在进化上是保守的。序列分析确定了植物TC中高度保守的30个氨基酸C端结构域，而蓝细菌同源物中则不存在。vte1-2导致该C端结构域的截短，导致的突变表型表明该结构域对于植物中的TC活性是必需的。sxd1中的蔗糖缺陷表明，除了预期的抗氧化活性外，生育酚或生育酚降解产物还起到信号转导分子的作用，或者是sxd1中积累的DMPBQ干扰了玉米高效蔗糖导出所需的信号传递。