Substrate specificity of the citrate transporter CitP of Lactococcus lactis.

ABSTRACT: The citrate transporter CitP of lactic acid bacteria catalyzes electrogenic precursor-product exchange of citrate versus L-lactate during citrate-glucose cometabolism. In the absence of sugar, L-lactate is replaced by the metabolic intermediates/end products pyruvate, α-acetolactate, and acetate. In this study, the binding and translocation properties of CitP were analyzed systematically for a wide variety of mono- and dicarboxylates of the form X-CR(2)-COO(-), where X represents OH (2-hydroxy acid), O (2-keto acid), or H (acid) and R groups differ in size, hydrophobicity, and composition. It follows that CitP is a very promiscuous carboxylate transporter. A carboxylate group is both essential and sufficient for recognition by the transporter. A C-2 atom is not essential, formate is a subs

SUBMITTER: Pudlik AM 

PROVIDER: S-EPMC3393487 | biostudies-literature | 2012 Jul

REPOSITORIES: biostudies-literature