Increased pyruvate orthophosphate dikinase activity results in an alternative gluconeogenic pathway in Rhizobium (Sinorhizobium) meliloti

Mutations that mediated the ability of Pck-deficient Rhizobium meliloti mutants to utilize succinate and tricarboxylic acid (TCA) intermediates were analyzed to characterize the biosynthesis of phosphoenolpyruvate (PEP). The activity of pyruvate orthophosphate dikinase (PPDK) in Rhizobium (Sinorhizobium) meliloti was enhanced by pckA suppressor mutations. Gluconeogenesis from malate in the pckA suppressor strain was also mediated by the combined activities of malic enzyme and PPDK.