Ubiquinone (coenzyme Q) biosynthesis in Escherichia coli: identification of the ubiF gene.
Ubiquinone (coenzyme Q) biosynthesis in Escherichia coli: identification of the ubiF gene.
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DOI：
10.1111/j.1574-6968.2000.tb09097.x
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发表时间：
2000-05
影响因子：
2.1
通讯作者：
O. Kwon;A. Kotsakis;R. Meganathan
中科院分区：
文献类型：
--
作者：
O. Kwon;A. Kotsakis;R. Meganathan
当氧或硝酸盐为电子受体时，泛醌（辅酶 Q；缩写 Q）在大肠杆菌的电子传递中起着重要作用。 Q的生物合成至少涉及九个反应。其中三个反应涉及羟基化，导致在 Q 苯核的 C-6、C-4 和 C-5 位置引入羟基。编码负责这些羟基化的酶 ubiB、ubiH 和 ubiF 的基因位于大肠杆菌连锁图的 87、66 和 15 分钟处。 ubiF 编码的加氧酶在 2-辛烯基-3-甲基-6-甲氧基-1,4-苯并喹啉的碳五处引入羟基，导致形成 2-辛烯基-3-甲基-5-羟基-6-甲氧基-1, 4-苯并喹啉。 ubiF 突变体未能进行这种转换。基于与UbiH的同源性，在染色体15分钟区域鉴定出开放阅读框（orf391），使用PCR扩增，并克隆到pUC18质粒中。当与该质粒互补时，ubiF 突变体重新获得了在琥珀酸上生长和合成 Q 的能力。
Ubiquinone (coenzyme Q; abbreviation, Q) plays an essential role in electron transport in Escherichia coli when oxygen or nitrate is the electron acceptor. The biosynthesis of Q involves at least nine reactions. Three of these reactions involve hydroxylations resulting in the introduction of hydroxyl groups at positions C-6, C-4, and C-5 of the benzene nucleus of Q. The genes encoding the enzymes responsible for these hydroxylations, ubiB, ubiH, and ubiF are located at 87, 66, and 15 min of the E. coli linkage map. The ubiF encoded oxygenase introduces the hydroxyl group at carbon five of 2-octaprenyl-3-methyl-6-methoxy-1,4-benzoquinol resulting in the formation of 2-octaprenyl-3-methyl-5-hydroxy-6-methoxy-1, 4-benzoquinol. An ubiF mutant failed to carry out this conversion. Based on the homology to UbiH, an open reading frame (orf391) was identified at the 15 min region of the chromosome, amplified using PCR, and cloned into pUC18 plasmid. The ubiF mutants, when complemented with this plasmid, regained the ability to grow on succinate and synthesize Q.