Our laboratory studies the regulation of CO2 fixation in phototrophic microorganisms. The expression of the enzymes responsible for assimilating CO2 is mainly regulated by a LysR-type transcriptional activator, CbbR, that functions by binding consensus sites in the promoter region of both Form I and Form II RubisCO operons under appropriate growth conditions. This straightforward model of regulation has a further level of complexity in the non-sulfur photosynthetic bacterium Rhodopseudomonas palustris. The recent genome sequencing project of this species identified a unique two-component system interposed between the structural genes of Form I RubisCO and CbbR. Two-component systems are a paradigm of gene regulation in Bacteria. In general, they consist of a sensor kinase and a response regulator, that upon stimulation transduce an external stimulus in a His-Asp phospho-relay ultimately modulating gene expression. The system identified in R. palustris in addition to a peculiar modular architecture, also has multiple PAS motifs, suggesting a complex redox sensing activity coordinating a multi-step phospho-relay, which regulates CO2 fixation under specific growth conditions.
Romagnoli S., Tabita FR (2006). Regulation of CO2 fixation in non-sulfur purple photosynthetic bacteria.. TOKYO : Springer.
Regulation of CO2 fixation in non-sulfur purple photosynthetic bacteria.
ROMAGNOLI, SIMONA;
2006
Abstract
Our laboratory studies the regulation of CO2 fixation in phototrophic microorganisms. The expression of the enzymes responsible for assimilating CO2 is mainly regulated by a LysR-type transcriptional activator, CbbR, that functions by binding consensus sites in the promoter region of both Form I and Form II RubisCO operons under appropriate growth conditions. This straightforward model of regulation has a further level of complexity in the non-sulfur photosynthetic bacterium Rhodopseudomonas palustris. The recent genome sequencing project of this species identified a unique two-component system interposed between the structural genes of Form I RubisCO and CbbR. Two-component systems are a paradigm of gene regulation in Bacteria. In general, they consist of a sensor kinase and a response regulator, that upon stimulation transduce an external stimulus in a His-Asp phospho-relay ultimately modulating gene expression. The system identified in R. palustris in addition to a peculiar modular architecture, also has multiple PAS motifs, suggesting a complex redox sensing activity coordinating a multi-step phospho-relay, which regulates CO2 fixation under specific growth conditions.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
