谷氨酸棒杆菌3-脱氧-α-阿拉伯庚酮糖酸-7磷酸合成酶基因的克隆与过量表达

本实验对谷氨酸棒杆菌(Corynebacterium glutamicum) AS10111及其亚硝基胍诱变获得的丙氨酸和酪氨酸双营养缺陷型、抗3- 甲基色氨酸突变菌株JLC1 中3- 脱氧- α- 阿拉伯庚酮糖酸-7 磷酸合成酶(DS)基因进行克隆和序列分析，将突变体来源DS 基因构建pZ8-1-DSM 重组质粒，在谷氨酸棒杆菌突变株JLC1 中进行表达，重组菌株JLC1(pZ8-1-DSM)DS 酶活力分别是宿主菌和野生型菌株DS 酶活力的5.9 和7.3 倍，色氨酸产量达到14.90g/L，较宿主菌提高了65%。这表明通过在谷氨酸棒杆菌中过量表达3- 脱氧- α- 阿拉伯庚酮糖酸-7 磷酸合成酶基因可以有效提高该酶活力和色氨酸的产量。

Cloning and Over-expression of 3-Deoxy- α-arobino-heptulosonate -7-phosphate Synthase Gene in Corynebacterium glutamicum

Two 3-deoxy- α -arobino-heptulosonate-7-phosphate synthase (DS) genes from Corynebacterium glutamicum AS10111, and its alanine and tyrosine auxotrophic and anti-trimethyl-tryptophane mutant C. glutamicum JLC1 were cloned and sequenced. The recombinant plasmid pZ8-1-DSM was constructed by using the DS gene from C. glutamicum JLC1 and expressed in transformed C. glutamicum JLC1. The results showed that the DS activity of recombinant C. glutamicum JLC1 (pZ8-1-DSM)is 5.9 and 7.3 times of that of the host and C. glutamicum wild-type strains, respectively, and its L-tryptophan yield reaches 14.9 g/L, highter 65% than that of the host strain. In conclusion, the DS activity and L-tryptophan yield can be effectively improved by over-expression of DS gene in Corynebacterium glutamicum.