Scheme 1
De novo folate biosynthesis pathway in S. stipitis. A Two main building blocks of folate derive from GTP (highlighted in purple) and pABA (highlighted in blue). GTP is produced in the purine biosynthesis pathway. pABA derives from chorismate, the last metabolite produced in the shikimate pathway which has E4P and PEP as precursors (highlighted in black). The first intermediate is produced in the PPP pathway (in green), while the second metabolite is an important molecule mostly produced through glycolysis (in red). The arrow thickness suggests a different flux distribution through the pathways depending on the carbon source. B Representation of the pathway in which the different vitamers of vitamin B9 are produced. Glc = glucose; Xyl = xylose; Glc-6P = glucose 6-phosphate; PPP = pentose phosphate pathway; E4P = erythrose 4-phospate; PEP = phosphoenolpyruvate; DHAP = 3-deoxy-d-arabino-heptulosonate-7-phosphate; DPM-PP = (7,8-dihydropterin-6-yl)methyl diphosphate; pABA = para-aminobenzoic acid; H2-pteroate = dihydropteroate; THF = tetrahydrofolate; DHF = dihydrofolate; Gly = glycine; Ser = serine; Glu = glutamate