Identification of two genes, sll0804 and slr1306, as putative components of the CO2-concentrating mechanism in the cyanobacterium Synechocystis sp. strain PCC 6803.

Insertional transposon mutations in the sll0804 and slr1306 genes were found to lead to a loss of optimal photoautotrophy in the cyanobacterium Synechocystis sp. strain PCC 6803 grown under ambient CO(2) concentrations (350 ppm). Mutants containing these insertions (4BA2 and 3ZA12, respectively) could grow photoheterotrophically on glucose or photoautotrophically at elevated CO(2) concentrations (50,000 ppm). Both of these mutants exhibited an impaired affinity for inorganic carbon. Consequently, the Sll0804 and Slr1306 proteins appear to be putative components of the carbon-concentrating mechanism in Synechocystis sp. strain PCC 6803.