Fig. 1
Schematic representation of the artificial pathway for the production of 4,3-AHBA from glucose in Corynebacterium glutamicum. Italic text indicates relevant genes in the pathway. Blue text indicates genes whose corresponding protein expression was enhanced by the constitutive Ptuf promoter. Orange text indicates the heterologous pobA gene encoding 4-hydroxybenzoate 3-hydroxylase (PHBH), which is expressed for the 3-hydroxylation of 4-ABA. Red text indicates the disrupted gene. The indicated genes encode the following enzymes: zwf, glucose 6-phosphate dehydrogenase; pgl, 6-phosphogluconolactonase; tkt, transketolase; tal, transaldolase; pyk, pyruvate kinase; ppsA, phosphoenolpyruvate synthase; aroF and aroG, DAHP synthase; aroB, 3-dehydroquinate synthase; qsuC, 3-dehydroquinate dehydratase; qsuB, dehydroshikimate dehydratase; qsuD and aroE, shikimate dehydrogenase; aroK, shikimate kinase; aroA, 5-enolpyruvylshikimate-3-phosphate synthase; aroC, chorismate synthase; pabAB, ADC synthase; pabC, ADC lyase; and pobA, PHBH. The abbreviations of the metabolites are: GLC, glucose; G6P, glucose-6-phosphate; F6P, fructose-6-phosphate; GAP, glyceraldehyde 3-phosphate; PEP, phosphoenolpyruvate; PYR, pyruvate; TCA, tricarboxylic acid; Ru5P, ribulose-5-phosphate; X5P, xylulose-5-phosphate; R5P, ribose-5-phosphate; S7P, sedoheptulose-7-phosphate; E4P, erythrose-4-phosphate; DAHP, 3-deoxy-D-arabino-heptulosonate-7-phosphate; DHQ, 3-dehydroquinate; QA, quinate; DHS, 3-dehydroshikimate; PCA, protocatechuate; SHK, shikimate; S3P, shikimate-3-phosphate; E3P, 5-enolpyruvylshikimate-3-phosphate; CHR, chorismate; ADC, 4-amino-4-deoxychorismate; 4-ABA, 4-aminobenzoic acid; and 4,3-AHBA, 4-amino-3-hydroxybenzoic acid