Fig 2.

Hypothetical model of the complex regulatory network of the quinoprotein ethanol oxidation system in P. aeruginosa. In the present study, gene ercA (PA1991), which encodes a Fe-ADH, was identified to be essential for expression of the ethanol oxidation system. The hierarchical arrangement of sensor kinases and response regulators control the expression of QEDH, cytochrome c₅₅₀, and PQQ biosynthetic enzymes (8). Solid arrows indicate demonstrated positive control of transcription, and broken arrows indicate assumed positive control of transcription. The identified genes encoding sensor kinases S and response regulators R are shown in a larger font size with the respective gene numbers. The proposed corresponding two-component system genes not yet identified are shown in a smaller font size. Two slashes indicate response regulator-sensor kinase pairing. This figure is a modified version of Fig. 3 from our previous publication (8).