Figure 3

Biosynthetic pathways for the production of diverse aromatic metabolites by combination of heterologous expression modules with the overproduction of intermediates from SHK- and terminal L-TYR pathways in Escherichia coli. PDC (2-pyrone-4,6-dicarboxylic acid) from DHS and CHA: (a) aroF ^fbr and aroB of E. coli; (b) ubiC (chorismate pyruvate-lyase) and pobA (4-hydroxybenzoate hydroxylase) of E. coli and Pseudomonas putida, respectively; (c) LigAB (protocatechuate 4,5-dioxygenase) and LigC (CHMS dehydrogenase) of Sphingobium sp. SYK-6 and qutC (dehydroshikimate dehydratase) of Emericella (Aspergillus) nidulans[100]. (S)-Reticuline from L-TYR: (d) tyrA ^fbr, aroG ^fbr, tktA and ppsA of E. coli; (e) NCS (norcoclaurine synthetase) of Coptis japonica, TYR (tyrosinase) of Streptomyces castaneoglobisporus, DODC (DOPA decarboxylase) of Pseudomonas putida and MAO (monoamine oxidase) of Micrococcus luteus; (f) 6OMT (norcoclaurine 6-O-methyltransferase), 4′OMT (3′-hydroxy-N-methylcoclaurine 4′-O-methyltransferase) and CNMT (coclaurine-N-methyltransferase) of C. japonica[97]. Hydroxytyrosol from L-TYR via 3,4-DHPAA (3,4-dihydroxyphenylacetaldehyde): (g) PCD (pterin-4 alpha-carbinolamine dehydratase) and DHPR (dihydropteridine reductase) of human and TH (tyrosine hydroxylase) of mouse; (h) DDC (L-DOPA decarboxylase) of pig and TYO (tyramine oxidase) of M. luteus[106]. Avenanthramides AvnD [N-(4′-hydroxycinnamoyl)-anthranilic acid] and AvnF [N-(3′,4′-dihydroxycinnamoyl)-anthranilic acid] from L-TYR and ANT: AvnDF module, tal (tyrosine ammonia-lyase) of Rhodotorula glutinis, 4CL1 (4-coumarate-CoA ligase) of Nicotiana tabacum, COUA3H (SAM5) (p-coumarate 3-hydroxylase) of Saccharothrix espanesis, HCBT (hydroxycinnamoyl/benzoyl-CoA/anthranilate N-hydroxycinnamoyl/benzoyltransferase) of Dianthus caryophyllus and hpaBC (code for an endogenous hydroxylase) of E. coli. SHK and TYR modules contain endogenous genes of E. coli[56]. PCA (protocatechuate); CHMS (4-carboxy-2-hydroxymuconate-6-semialdehyde); CAFA (caffeate); CAF-CoA (caffeoyl-CoA); COUA (p-coumarate); COU-CoA (p-coumaroyl-CoA); adhP (alcohol dehydrogenase of E. coli). p, indicates plasmid expression module. ^fbr, feedback resistant gene. ^op, codon-optimized gene. ↱, promoter. NER, Non-enzymatic reaction.