Title: Up-Regulated Expression of the <i> cbb <sub>I</sub> </i> and <i> cbb <sub>II</sub> </i> Operons during Photoheterotrophic Growth of a Ribulose 1,5-Bisphosphate Carboxylase-Oxygenase Deletion Mutant of <i>Rhodobacter sphaeroides</i>
Abstract: ABSTRACT In a Rhodobacter sphaeroides ribulose 1,5-bisphosphate carboxylase-oxygenase deletion strain that requires an exogenous electron donor for photoheterotrophic growth, transcription of the genes of the Calvin-Benson-Bassham (CBB) cycle was increased. This finding pointed to a potential physiological effector that enhances the capability of the positive transcriptional activator CbbR to mediate cbb transcription. This effector is most likely ribulose 1,5-bisphosphate or a metabolite derived from this CBB pathway intermediate.