Identification of a novel gene cluster participating in menaquinone (vitamin K-2) biosynthesis - Cloning and sequence determination of the 2-heptaprenyl-1,4-naphthoquinone methyltransferase gene of Bacillus stearothermophilus
Identification of a novel gene cluster participating in menaquinone (vitamin K-2) biosynthesis - Cloning and sequence determination of the 2-heptaprenyl-1,4-naphthoquinone methyltransferase gene of Bacillus stearothermophilus
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DOI：
10.1074/jbc.272.19.12380
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发表时间：
1997-05-09
影响因子：
4.8
通讯作者：
Ogura, K
中科院分区：
文献类型：
--
作者：
KoikeTakeshita, A;Koyama, T;Ogura, K
我们最近分离和序列分析了嗜热脂肪芽孢杆菌七烯基二磷酸合成酶基因的DNA区域，序列分析显示该细菌的七氢喹酮-7的戊烯基侧链的合成存在三个开放阅读框(ORF)，分别命名为ORF-1、ORF-2和ORF-3，结构基因由ORF-1(heps-1)和ORF-3(heps-2)组成(Koike-Takeshita，A.，Koyama，T.，Obata，S.和Ogura，K.(1995)J.化学。18396-18400)。预测的ORF-2氨基酸序列(234个氨基酸)包含一个甲基转移酶共同序列，与大肠杆菌的UBIG有22%的同源性，UBIG催化S-腺苷-L-蛋氨酸依赖的2-octaprenyl-3-methyl-5-hydroxy-6-methoxy-1，4-benzoquinone.甲基化。这些信息使我们确定了ORF-2基因产物。转化子与ORF-2表达载体的无细胞匀浆催化了S-腺苷-L-蛋氨酸的掺入，表明ORF-2编码2-七烯基-1，4-萘醌甲基转移酶，参与了菜醌生物合成的最后一步。因此，ORF-1、ORF-2和ORF-3基因分别命名为heps-1、eng和heps-2，形成了除已在枯草芽孢杆菌和大肠杆菌染色体中发现的MenB、MenC、Mend和Mene之外的另一个参与菜籽酮生物合成的簇。
We recently described the isolation and sequence analysis of a DNA region containing the genes of Bacillus stearothermophilus heptaprenyl diphosphate synthase, which catalyzes the synthesis of the prenyl side chain of menaquinone-7 of this bacterium, Sequence analyses revealed the presence of three open reading frames (ORFs), designated as ORF-1, ORF-2, and ORF-3, and the structural genes of the heptaprenyl diphosphate synthase were proved to consist of ORF-1 (heps-1) and ORF-3 (heps-2) (Koike-Takeshita, A., Koyama, T., Obata, S., and Ogura, K. (1995) J. Biol. Chem. 270, 18396-18400). The predicted amino acid sequence of ORF-2 (234 amino acids) contains a methyltransferase consensus sequence and shows a 22% identity with UbiG of Escherichia coli, which catalyzes S-adenosyl-L-methionine-dependent methylation of 2-octaprenyl-3-methyl-5-hydroxy-6-methoxy-1,4-benzoquinone. These pieces of information led us to identify the ORF-2 gene product. The cell-free homogenate of the transformant of E. coli with an expression vector of ORF-2 catalyzed the incorporation of S-adenosyl-L-methionine into menaquinone-8, indicating that ORF-2 encodes 2-heptaprenyl-1,4-naphthoquinone methyltransferase, which participates in the terminal step of the menaquinone biosynthesis. Thus it is concluded that the ORF-1, ORF-2, and ORF-3 genes, designated heps-1, menG, and heps-2, respectively, form another cluster involved in menaquinone biosynthesis in addition to the cluster of menB, menC, menD, and menE already identified in the Bacillus subtilis and E. coli chromosomes.