atp Mutants of Escherichia coli Fail To Grow on Succinate Due to a Transport Deficiency

Abstract

ABSTRACT Escherichia coli atp mutants, which lack a functional H + -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 H + -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.