atp mutants of Escherichia coli fail to grow on succinate due to a transport deficiency

Escherichia coli atp mutants, which lack a functional Hf-ATPase complex, are capable of growth on glucose but not on succinate or other C-4-dicarboxylates (Suc(-) phenotype). Suc(+) revertants of an atp deletion strain were isolated which were capable of growth on succinate even though they lack the entire Hf-ATPase complex. Complementation in trans with the yhiF gene suppressed the growth of the Suc(+) mutants on succinate, which implicates the yhiF gene product in the regulation of C-4-dicarboxylate metabolism. Indeed, when the E. coli C-4-dicarboxylate transporter (encoded by the dctA gene) was expressed in trans, the Suc(-) phenotype of the atp deletion strain reverted to Suc(+), which shows that the reason why the E. coli atp mutant is unable to grow aerobically on C-4-dicarboxylates is insufficient transport capacity for these substrates.