A global signal transduction system regulates aerobic and anaerobic CO2 fixation in Rhodobacter sphaeroides

The role of the regB gene in bacterial signal transduction and CO2 fixation regulation in Rhodobacter sphaeroides was studied. Results revealed that aside from photosystem synthesis, the gene also plays a crucial role in the control of the Calvin cycle CO2 fixation operon. When light is available, regulation proceeds anaerobically. In the dark, however, it occurs aerobically. This suggests that regB belongs to a two-component system which codes for a sensor kinase controlling the regulation of light-independent and dependent CO2 fixation and the biosynthesis of the photosystem.