重组产番茄红素大肠杆菌工程菌株中异戊烯异构酶(IDI)基因的筛选
Screening of isopentenyl diphosphate isomerase( IDI)in engineering Escherichia coli strains for lycopene production
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摘要: 番茄红素是一类在食品、医药等领域具有广泛应用价值的萜类化合物。异戊烯基焦磷酸异构酶（isopentenyl diphosphate isomerase,IDI）是番茄红素合成途径中的关键酶,也是代谢工程改造的主要靶点。本研究为了系统比较不同来源IDI对重组大肠杆菌番茄红素（Lycopene）产量的影响,分别克隆了原核微生物、真核微生物、植物、古菌等多种来源的I型及II型异戊烯基焦磷酸异构酶（IDI）基因,在大肠杆菌E.coli中异源表达,在加强自身2-C-甲基-D-赤藓糖醇-4-磷酸（MEP）代谢途径的背景下,通过优化多靶点组合及转化时间提高番茄红素的合成水平。结果表明酿酒酵母来源的I型IDI（Sc IDI）及枯草芽孢杆菌来源的II型IDI（Bs IDI）在经优化的背景下可以获得最高的番茄红素产量,产量分别达到9.96 mg/g DCW,8.78 mg/g DCW,番茄红素积累在转化8 h达到最高,最高能达到10.29 mg/g DCW。本研究最终确定了不同类型IDI发挥功能的条件,为后续番茄红素以及萜类化合物的代谢途径的改造提供依据。Abstract: Lycopene is a terpenoid pigment that has diverse applications in the fields of food and medicine. A prospective approach for lycopene production is by metabolic engineering in microbial hosts such as Escherichia coli.Isopentenyl diphosphate isomerase( IDI) is the key enzyme in lycopene biosynthetic pathway,and one of the most important targets during metabolic engineering. In this study,in order to systematic compare the effects of different IDI on lycopene production,the type1 and type2 genes of isopentenyl diphosphate isomerase were cloned from different species,including prokaryotic microbe,eukaryotic microbe,plant,archaea,and heterologous expressed in Escherichia coli.The effects of different IDI on lycopene production and the bioconversional conditions were investigated in a MEP- enhanced background in Escherichia coli.In the result,Sc IDI and Bs IDI were the most efficient IDI species for lycopene production and the yield of lycopene rose to 9.96 mg / g DCW,8.78 mg / g DCW.As observed after bioconversion for 8 h,the yield of lycopene was up to a maximum of 10.29 mg / g DCW.The results will provide new information for further metabolic engineering study involved in lycopene and terpenoid production.
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