Okada K, Suzuki K, Kamiya Y, Zhu X, Fujisaki S, Nishimura Y, Nishino T, Nakagawa T, Kawamukai M, Matsuda H
Department of Applied Bioscience and Biotechnology, Faculty of Life and Environmental Science, Shimane University, Matsue, Japan.
Biochim Biophys Acta. 1996 Aug 16;1302(3):217-23. doi: 10.1016/0005-2760(96)00064-1.
Ubiquinone, known as a component of the electron transfer system in many organisms, has a different length of the isoprenoid side chain depending on the species, e.g., Escherichia coli, Saccharomyces cerevisiae and humans have 8, 6, and 10 isoprene units in the side chain, respectively. No direct evidence has yet shown what factors define the length of the side chain of ubiquinone. Here we proved that the polyprenyl diphosphate that was available in cells determined the length of the side chain of ubiquinone. E. coli octaprenyl diphosphate synthase (IspB) was expressed with the mitochondrial import signal in S. cerevisiae. Such cells produced ubiquinone-8 in addition to the originally existing ubiquinone-6. When IspB was expressed in a S. cerevisiae COQ1 defective strain. IspB complemented the defect of the growth on the non-fermentable carbon source. Those cells had the activity of octaprenyl diphosphate synthase and produced only ubiquinone-8. These results opened the possibility of producing the type of ubiquinone that we need in S. cerevisiae simply by expressing the corresponding polyprenyl diphosphate synthase.
泛醌作为许多生物体中电子传递系统的一个组成部分，其异戊二烯侧链的长度因物种而异，例如，大肠杆菌、酿酒酵母和人类的侧链中分别含有8个、6个和10个异戊二烯单元。尚无直接证据表明是什么因素决定了泛醌侧链的长度。在此我们证明，细胞中可用的聚异戊二烯二磷酸决定了泛醌侧链的长度。大肠杆菌八聚异戊二烯二磷酸合酶（IspB）在线粒体导入信号的作用下在酿酒酵母中表达。这样的细胞除了原本存在的泛醌-6之外，还产生了泛醌-8。当IspB在酿酒酵母COQ1缺陷菌株中表达时，IspB弥补了在非发酵碳源上生长的缺陷。这些细胞具有八聚异戊二烯二磷酸合酶的活性，并且只产生泛醌-8。这些结果开启了通过简单地表达相应的聚异戊二烯二磷酸合酶在酿酒酵母中生产我们所需类型泛醌的可能性。
