Kennedy J, Turner G
Department of Molecular Biology and Biotechnology, Krebs Institute for Biomolecular Research, University of Sheffield, UK.
Mol Gen Genet. 1996 Nov 27;253(1-2):189-97. doi: 10.1007/s004380050312.
The acvA gene from Aspergillus nidulans encoding delta-(L-alpha-aminoadipyl)-L-cysteinyl-D-valine (ACV) synthetase was overexpressed by replacing the wild-type acvA promoter with the ethanol dehydrogenase promoter, alcAp, from A. nidulans. The expression level of alcAp was determined using a strain in which the reporter gene, lacZ, is under the control of alcAp, and was found to be up to 100 times greater than that from the acvA promoter when induced in fermentation conditions. Penicillin yields were found to increase by as much as 30-fold when the acvA gene was overexpressed. Glucose, which strongly represses transcription from alcAp, also repressed penicillin biosynthesis in the overexpression strain. These results prove that ACV synthetase is a rate limiting enzyme for penicillin production in A. nidulans.
通过用来自构巢曲霉的乙醇脱氢酶启动子alcAp替换野生型acvA启动子，使构巢曲霉中编码δ-（L-α-氨基己二酰基）-L-半胱氨酰-D-缬氨酸（ACV）合成酶的acvA基因过表达。使用报告基因lacZ受alcAp控制的菌株测定alcAp的表达水平，发现在发酵条件下诱导时，其表达水平比acvA启动子的表达水平高多达100倍。当acvA基因过表达时，青霉素产量增加了多达30倍。强烈抑制alcAp转录的葡萄糖也抑制了过表达菌株中的青霉素生物合成。这些结果证明ACV合成酶是构巢曲霉中青霉素生产的限速酶。
