title: Genetic engineering of Escherichia coli for production of tetrahydrobiopterin.
abstract: Tetrahydrobiopterin (BH4) is an essential cofactor for various enzymes in mammals. In vivo, it is synthesized from GTP via the three-step pathway of GTP cyclohydrolase I (GCHI), 6-pyruvoyl-tetrahydropterin synthase (PTPS) and sepiapterin reductase (SPR). BH4 is a medicine used to treat atypical hyperphenylalaninemia. It is currently synthesized by chemical means, which consists of many steps, and requires costly materials and complicated procedures. To explore an alternative microbial method for BH4 production, we utilized recombinant DNA technology to construct recombinant Escherichia coli (E. coli) strains carrying genes expressing GCHI, PTPS and SPR enzymes. These strains successfully produced BH4, which was detected as dihydrobiopterin and biopterin, oxidation products of BH4. In order to increase BH4 productivity we made further improvements. First, to increase the de novo GTP supply, an 8-azaguanine resistant mutant was isolated and an additional guaBA operon was introduced. Second, to augment the activity of GCHI, the folE gene from E. coli was replaced by the mtrA gene from Bacillus subtilis. These modifications provided us with a strain showing significantly higher productivity, up to 4.0 g of biopterin/L of culture broth. The results suggest the possibility of commercial BH4 production by our method.
authors.affiliation: Bioprocess Development Group, Institute for Medicinal Research and Development, Daiichi Suntory Pharma Co., Ltd. 2716-1 Kurakake, Akaiwa, Chiyoda-machi, Ohra-gun, Gunma 370-0503, Japan. katsuhiko_yamamoto@dsup.co.jp
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Yamamoto
authors.forename: Eri
authors.initials: E
authors.lastname: Kataoka
authors.forename: Nobue
authors.initials: N
authors.lastname: Miyamoto
authors.forename: Kazuaki
authors.initials: K
authors.lastname: Furukawa
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Ohsuye
authors.forename: Masayuki
authors.initials: M
authors.lastname: Yabuta
mesh_terms: D000429:Alcohol Oxidoreductases / Q000378:metabolism; D001708:Biopterins / Q000031:analogs & derivatives* / Q000096:biosynthesis* / Q000235:genetics* / Q000302:isolation & purification; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism*; D006136:GTP Cyclohydrolase / Q000235:genetics / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology*; D005818:Genetic Engineering / Q000379:methods*; D009097:Multienzyme Complexes / Q000235:genetics / Q000378:metabolism; D019761:Phosphorus-Oxygen Lyases / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism
chemical_list: D009097:Multienzyme Complexes; D011994:Recombinant Proteins; D001708:Biopterins; D000429:Alcohol Oxidoreductases; C022630:sepiapterin reductase; D006136:GTP Cyclohydrolase; D019761:Phosphorus-Oxygen Lyases; C043497:6-pyruvoyltetrahydropterin synthase; C003402:sapropterin