Okada K, Minehira M, Zhu X, Suzuki K, Nakagawa T, Matsuda H, Kawamukai M
Department of Applied Bioscience and Biotechnology, Faculty of Life and Environmental Science, Shimane University, Matsue, Japan.
J Bacteriol. 1997 May;179(9):3058-60. doi: 10.1128/jb.179.9.3058-3060.1997.
The Escherichia coli ispB gene encoding octaprenyl diphosphate synthase is responsible for the synthesis of the side chain of isoprenoid quinones. We tried to construct an E. coli ispB-disrupted mutant but could not isolate the chromosomal ispB disrupted mutant unless the ispB gene or its homolog was supplied on a plasmid. The chromosomal ispB disruptants that harbored plasmids carrying the ispB homologs from Haemophilus influenzae and Synechocystis sp. strain PCC6803 produced mainly ubiquinone 7 and ubiquinone 9, respectively. Our results indicate that the function of the ispB gene is essential for normal growth and that this function can be substituted for by homologs of the ispB gene from other organisms that produce distinct forms of ubiquinone.
编码八聚异戊二烯二磷酸合酶的大肠杆菌ispB基因负责类异戊二烯醌侧链的合成。我们试图构建一个ispB基因敲除的大肠杆菌突变体，但除非在质粒上提供ispB基因或其同源物，否则无法分离出染色体ispB基因敲除的突变体。携带来自流感嗜血杆菌和集胞藻属PCC6803菌株的ispB同源物的质粒的染色体ispB基因敲除突变体分别主要产生泛醌7和泛醌9。我们的结果表明，ispB基因的功能对于正常生长至关重要，并且该功能可以被来自产生不同形式泛醌的其他生物体的ispB基因同源物所替代。
