FIGURE 5: Network position of purH suppressor mutations. Loss-of-function mutations that suppress the thiamine requirement of a purH mutant have a role in various aspects of central carbon metabolism. The cyaA gene encodes adenylate cyclase and its product (cAMP) is the effector of the CRP transcriptional regulator that modulates >100 genes [45]. The mtfA gene encodes the Mlc titration factor; Mlc is a global regulator of sugar metabolism. Both cAMP-CRP and MtfA are part of the PTS signal transduction pathway [46]. Fumarate dehydratase (fumAC) and glutamate dehydrogenase (gdhA) function in, or just peripheral to, the TCA cycle. Glucose-6-phosphate dehydrogenase (zwf) is the first enzyme of the oxidative pentose phosphate pathway.

45. Kolb A, Busby S, Buc H, Garges S, Adhya S (1993). Transcriptional regulation by cAMP and its receptor protein. Annual Rev Biochem 62:749-795. https://doi.org/10.1146/annurev.bi.62.070193.003533

46. Becker AK, Zeppenfeld T, Staab A, Seitz S, Boos W, Morita T, Aiba H, Mahr K, Titgemeyer F, Jahreis K (2006). YeeI, a novel protein involved in modulation of the activity of the glucose-phosphotransferase system in Escherichia coli K-12. J Bacteriol 188(15): 5439-5449. https://doi.org/10.1128/JB.00219-06