Department of Chemical and Environmental Engineering, University of California, Riverside, California 92521, USA.
Biotechnol Bioeng. 2010 Mar 1;105(4):780-5. doi: 10.1002/bit.22585.
Phytochelatin (PC) is a naturally occurring peptide with high affinity towards arsenic (As). In this article, we demonstrated the systematic engineering of PC-producing E. coli for As accumulation by addressing different bottlenecks in PC synthesis as well as As transport. Phytochelatin synthase from Schizosaccharomyces pombe (SpPCS) was expressed in E. coli resulting in 18 times higher As accumulation. PC production was further increased by co-expressing a feedback desensitized gamma-glutamylcysteine synthetase (GshI*), resulting in 30-fold higher PC levels and additional 2-fold higher As accumulation. The significantly increased PC levels were exploited further by co-expressing an arsenic transporter GlpF, leading to an additional 1.5-fold higher As accumulation. These engineering steps were finally combined in an arsenic efflux deletion E. coli strain to achieve an arsenic accumulation level of 16.8 micromol/g DCW, a 80-fold improvement when compared to a control strain not producing phytochelatins.
植物螯合肽（PC）是一种对砷（As）具有高亲和力的天然存在的肽。在本文中，我们通过解决 PC 合成以及 As 转运中的不同瓶颈，展示了用于砷积累的产 PC 大肠杆菌的系统工程。来自酿酒酵母（Schizosaccharomyces pombe）的 PC 合酶（SpPCS）在大肠杆菌中表达，导致砷积累增加 18 倍。通过共表达反馈脱敏的γ-谷氨酰半胱氨酸合成酶（GshI*）进一步增加 PC 的产生，导致 PC 水平增加 30 倍，砷积累增加 2 倍。进一步利用显着增加的 PC 水平共表达砷转运蛋白 GlpF，导致砷积累增加 1.5 倍。这些工程步骤最终在砷外排缺失大肠杆菌菌株中结合，实现了 16.8 微米摩尔/克 DCW 的砷积累水平，与不产生植物螯合肽的对照菌株相比提高了 80 倍。
