弱氧化葡糖杆菌ddsA基因在大肠杆菌不同宿主菌中的表达

Production of ubiquinone in various Escherichia coli hosts by expression of ddsA gene from Gluconobacter suboxydans

泛醌 (辅酶Q)在生物体氧化呼吸链中作为重要的质子和电子传递物质。聚十异戊烯焦磷酸合成酶催化辅酶Q10 的侧链的生物合成。为了获得高产辅酶Q10 的菌株 ,将选择了 10种不同大肠杆菌宿主菌用于弱氧化葡糖杆菌的聚十异戊烯焦磷酸合成酶基因ddsA的表达 ,通过产物分析证实该基因能在大肠杆菌中表达出有活性的聚十异戊烯焦磷酸合成酶 ,使大肠杆菌合成了辅酶Q10 。此外 ,还发现在EscherichiacoliHB10 1这一菌株中 ,ddsA的表达使辅酶Q10 的产量略超过了在野生型中占主导地位的辅酶Q8的产量。该结果证明了利用大肠杆菌大规模发酵生产辅酶Q10 的可能性。

Ubiquinone (Coenzyme Q), known as a carrier of electrons and protons is a redox-active lipid essential in aerobic respiration. Decaprenyl diphosphate synthases catalyzes the synthesis of long-chain isoprenoids. In order to get an excellent ubiquinone(-10) producer, 10 kinds of Escherichia coli were selected to express the Gluconobacter suboxydans decaprenyl diphosphate synthase gene ddsA. With the expression of the gene, most of the transformants produced ubiquinone(-10) ,which hardly exists in their wild types. The finding of a strain Escherichia coli HB101, which produced almost the same amount of ubiquinone(-10) and ubiquinone(-8), proved the possibility of efficient ubiquinone(-10) production in E.coli cells suitable for large-scale fermentation.