PUB - Publikationen an der Universität Bielefeld

Transporters of the dicarboxylate amino acid-cation symporter family often mediate uptake of C-4-dicarboxylates, such as succinate or L-malate, in bacteria. A member of this family, dicarboxylate transporter A (DctA) from Corynebacterium glutamicum, was characterized to catalyze uptake of the C-4-dicarboxylates succinate, fumarate, and L-malate, which was inhibited by oxaloacetate, 2-oxoglutarate, and glyoxylate. DctA activity was not affected by sodium availability but was dependent on the electrochemical proton potential. Efficient growth of C. glutamicum in minimal medium with succinate, fumarate, or L-malate as the sole carbon source required high dctA expression levels due either to a promoter-up mutation identified in a spontaneous mutant or to ectopic overexpression. Mutant analysis indicated that DctA and DccT, a C-4-dicarboxylate divalent anion/sodium symporter-type transporter, are the only transporters for succinate, fumarate, and L-malate in C. glutamicum.