大肠杆菌色氨酸生物合成途径关键酶的调控研究  

Regulation of Key Enzymes in Tryptophan Biosynthesis Pathway in Escherichia coli

作　　者：于金龙[1] 王静[2] 李剑欣[1] 郭长江[3] 黄英武[4] 徐琪寿[1] 

机构地区：[1]军事医学科学院放射与辐射医学研究所,北京100850 [2]河南中医学院基础医学院,郑州450008 [3]军事医学科学院卫生学与环境医学研究所,天津300050 [4]中国人民解放军306医院中心实验室,北京100101

出　　处：《生物工程学报》2008年第5期844-850,共7页Chinese Journal of Biotechnology

基　　金：国家自然科学基金(No.30300010)资助~~

摘　　要：为了通过基因工程手段提高大肠杆菌色氨酸产量,对色氨酸生物合成途径中的关键基因trpR、tnaA、aroG和trpED进行了改造。首先通过敲除trpR基因解除了基因组上色氨酸合成和转运关键酶受到的反馈阻遏调控,进而又敲除了tnaA基因,阻断了色氨酸的分解代谢。然后,将色氨酸合成途径的关键酶aroGfbr和trpEDfbr基因串联表达,以去除色氨酸生物合成途径的瓶颈。与对照MG1655相比,trpR基因单敲菌色氨酸浓度提高了10倍,双敲菌色氨酸浓度提高了约20倍。pZE12-trpEDfbr转入双敲菌后色氨酸浓度提高到168mg/L,而将aroGfbr和trpEDfbr转入双敲菌后,色氨酸浓度提高到820mg/L。为构建色氨酸高产菌奠定了基础。To improve tryptophan production in Escherichia coli, key genes in the tryptophan biosynthesis pathway -aroG, trpED, trpR and tnaA were manipulated. TrpR gene was knocked out to eliminate the repression on the key genes controlling tryptophan biosynthesis and transportation on bacteria chromosome, and the tryptophan degradation was blocked by maA gene knockout. Then the bottleneck in tryptophan biosynthesis pathway was removed by co-expressing aroC^fbr gene and trpE^fbr gene. Compared with the MG1655, the tryptophan production of trpR knockout and double-genes knockout strains was improved 10-folds and about 20-folds, respectively. After the trpE^fbr was expressed, the tryptophan production increased to 168 mg/L, and when the aroG^fbr and trpED^fbr were co-expressed, the tryptophan production increased to 820 mg/L. This work laid the foundation for further construction of higher-efficient engineered strain for tryptophan production.

关 键 词：aroG和trpED共表达 trpR和tnaA双敲除 色氨酸 

分 类 号：TQ922[轻工技术与工程—发酵工程] Q789[生物学—分子生物学]