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标题：Tuning the Binding Affinity of Heme-Responsive Biosensor for Precise and Dynamic Pathway Regulation
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作者：Jian Zhang ; Zhiguo Wang ; Tianyuan Su 等
期刊名称：iScience
印刷版ISSN：2589-0042
出版年度：2020
卷号：23
期号：5
页码：1-33
DOI：10.1016/j.isci.2020.101067
语种：English
出版社：Elsevier
摘要：SummaryCurrent challenge for dynamic pathway control in metabolic engineering is enabling the components of the artificial regulatory system to be tunable. Here, we designed and built a heme-responsive regulatory system containing a heme biosensor HrtR and CRISPRi to regulate chemicals production while maintaining the intracellular heme homeostasis. A series of engineered biosensors with varied sensitivity and threshold were obtained by semi-rational design with site saturated mutation of HrtR. The modified metabolite-binding affinity of HrtR was confirmed by heme titration and molecular dynamic simulation. Dynamic regulation pattern of the system was validated by the fluctuation of gene expression and intracellular heme concentration. The efficiency of this regulatory system was proved by improving the 5-aminolevulinic acid (ALA) production to 5.35g/L, the highest yield in batch fermentation ofEscherichia coli. This system was also successfully used in improving porphobilinogen (PBG) and porphyrins biosynthesis and can be applied in many other biological processes.Graphical AbstractDisplay OmittedHighlights•Designed and built a heme-responsive regulatory system employing HrtR and CRISPRi•Turning the binding affinity of HrtR by site saturation mutations•Optimizing the system to achieve dynamic regulation of target genes•The system was applied to the ALA, PBG, and porphyrins productionBioengineering; Metabolic Engineering; Biotechnology