Reduction in Phosphoribulokinase Amount and Re-Routing Metabolism in CP12 Mutants.

The chloroplast protein CP12 is involved in the dark/light regulation of the Calvin-Benson-Bassham cycle, in particular, in the dark inhibition of two enzymes: glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and phosphoribulokinase (PRK), but other functions related to stress have been proposed. We knocked out the unique gene to prevent its expression in (ΔCP12). The growth rates of both wild-type and ΔCP12 cells were nearly identical, as was the GAPDH protein abundance and activity in both cell lines.