Skip to main content


Fig. 1 | BMC Systems Biology

Fig. 1

From: Use of transcriptomic data for extending a model of the AppA/PpsR system in Rhodobacter sphaeroides

Fig. 1

Schematic diagrams for photosynthetic gene regulation and the existing model for the AppA/PpsR system. a A diagram of light and redox dependent regulation of photosynthesis genes by PrrB/A, AppA/PpsR and FnrL in Rhodobacter sphaeroides. Note that the FnrL system activates PS genes expression under anaerobic condition, in cooperation with PrrB/A, while it inhibits expression under aerobic conditions. Here, the red thick line with red arrow on top denotes expression, black arrows represent activation, and the line with bar end denotes inhibition of PS genes. The bidirectional arrow represents the phosphorylation and dephosphorylation of PrrB and PrrA. A dotted and zigzag line shows sensing of oxygen / redox and blue light, respectively. b The simple model for the light and redox dependent interaction of AppA and PpsR (copied from Pandey et al., 2011 [26] with permission). Here, [O2] represents the oxygen concentration and LI blue light irradiance. Oxidised and reduced forms of PpsR are denoted by tetrameters with disulfide bonds (S-S) and thiol groups (S-H), respectively. AppA has two cofactors attached: (i) FAD, and (ii) heme. The h+ and h represent oxidised and reduced form of heme cofactor, respectively. The lines with bar end denote repression of PS genes by PpsR, and the thickness of that shows the strength of repression; oxidised form of PpsR (PpsRox) is a strong repressor compared to the reduced form (PpsRred)

Back to article page