title: Optimization of the heme biosynthesis pathway for the production of 5-aminolevulinic acid in Escherichia coli.
abstract: 5-Aminolevulinic acid (ALA), the committed intermediate of the heme biosynthesis pathway, shows significant promise for cancer treatment. Here, we identified that in addition to hemA and hemL, hemB, hemD, hemF, hemG and hemH are also the major regulatory targets of the heme biosynthesis pathway. Interestingly, up-regulation of hemD and hemF benefited ALA accumulation whereas overexpression of hemB, hemG and hemH diminished ALA accumulation. Accordingly, by combinatorial overexpression of the hemA, hemL, hemD and hemF with different copy-number plasmids, the titer of ALA was improved to 3.25 g l(-1). Furthermore, in combination with transcriptional and enzymatic analysis, we demonstrated that ALA dehydratase (HemB) encoded by hemB is feedback inhibited by the downstream intermediate protoporphyrinogen IX. This work has great potential to be scaled-up for microbial production of ALA and provides new important insights into the regulatory mechanism of the heme biosynthesis pathway.
authors.affiliation: 1] The Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China [2] School of Biotechnology, Jiangnan University, Wuxi 214122, China [3] Synergetic Innovation Center of Food Safety and Nutrition, Jiangnan University, Wuxi, Jiangsu 214122, China.
authors.forename: Junli
authors.initials: J
authors.lastname: Zhang
authors.affiliation: 1] The Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China [2] School of Biotechnology, Jiangnan University, Wuxi 214122, China [3] Synergetic Innovation Center of Food Safety and Nutrition, Jiangnan University, Wuxi, Jiangsu 214122, China.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Kang
authors.affiliation: 1] School of Biotechnology, Jiangnan University, Wuxi 214122, China [2] Synergetic Innovation Center of Food Safety and Nutrition, Jiangnan University, Wuxi, Jiangsu 214122, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Chen
authors.affiliation: 1] School of Biotechnology, Jiangnan University, Wuxi 214122, China [2] The Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China.
authors.forename: Guocheng
authors.initials: G
authors.lastname: Du
mesh_terms: D000622:Aminolevulinic Acid / Q000378:metabolism*; D053898:Biosynthetic Pathways; D003001:Cloning, Molecular; D004794:Enzyme Repression; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism; D005294:Ferrochelatase / Q000235:genetics / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D006418:Heme / Q000096:biosynthesis*; D000623:Porphobilinogen Synthase / Q000235:genetics / Q000378:metabolism; D050768:Protoporphyrinogen Oxidase / Q000235:genetics / Q000378:metabolism; D011524:Protoporphyrins / Q000502:physiology; D015854:Up-Regulation
chemical_list: D029968:Escherichia coli Proteins; D011524:Protoporphyrins; D006418:Heme; C011539:protoporphyrinogen; D000622:Aminolevulinic Acid; C493977:HemG protein, E coli; D050768:Protoporphyrinogen Oxidase; D000623:Porphobilinogen Synthase; D005294:Ferrochelatase