25-04-2019 дата публикации
Номер: US20190119663A1
Принадлежит:
Described herein are recombinant microbial host cells comprising biosynthetic pathways and their use in producing oxidation products and downstream products, e.g., melatonin and related compounds, as well as enzyme variants, nucleic acids, vectors and methods useful for preparing and using such cells. In specific aspects, the present invention relates to monooxygenases, e.g., amino acid hydroxylases, with a modified cofactor-dependency, and to enzyme variants and microbial cells providing for an improved supply of cofactors. 1E. coliE. coli. A variant of GTP cyclohydrolase I (GCH1) having at least about 80% sequence identity to native GCH1 (SEQ ID NO:16) and comprising one or more mutations , wherein ,{'i': E. coli', 'E. coli, 'in an cell comprising a pterin-4α-carbinolamine dehydratase (PCD) and at least one of a tryptophan hydroxylase (TPH), a tyrosine hydroxylase (TH) and a phenylalanine hydroxylase (PheH), the variant provides for an increased hydroxylation activity of at least one of the TPH, TH and PheH as compared to native GCH1, and'}the mutation is not T198P.2. The variant of claim 1 , wherein at least one of the one or more mutations is in an amino acid residue in a segment selected from D97-E112 claim 1 , K121-D130 claim 1 , N170-H180 claim 1 , S193-L200 and S207-N222.3. The variant of claim 1 , wherein at least one of the one or more mutations is in an amino acid residue selected from the group consisting of D97 claim 1 , M99 claim 1 , T101 claim 1 , V102 claim 1 , A125 claim 1 , K129 claim 1 , N170 claim 1 , V179 claim 1 , T196 claim 1 , T198 claim 1 , S199 claim 1 , L200 claim 1 , S207 claim 1 , H212 claim 1 , E213 claim 1 , F214 claim 1 , L215 and H221.4. The variant of claim 1 , wherein the variant(a) comprises a mutation selected from D97V, D97L, D97A, D97T, M99C, M99T, M99V, M99L, M99I, T101I, T101V, T101L, V102M, N170K, N170D, N170L, V179A, V179M, T196I, T196V, T196L, T198I, T198V, T198S, T198L, S199Y, S199F, L200P, L200C, L200S, L200A, S207R, ...
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