C4-dicarboxylate metabolons: interaction of C4-dicarboxylate transporters of Escherichia coli with cytosolic enzymes. Issue 1 (31st August 2022)

• Record Type: Journal Article
• Authors: Schubert, Christopher; Kim, Nam Yeun; Unden, Gottfried; Kim, Ok Bin
• Is Part Of: FEMS microbiology letters. Volume 369:Issue 1(2022)
• Publication Date: 2022-08-31
• Subjects: metabolon -- C4-dicarboxylate transporter -- L-aspartate -- Escherichia coli -- BACTH -- mSPINE; Microbiology -- Periodicals; 579
• DOI: 10.1093/femsle/fnac078
• Languages: English
• ISSNs: 0378-1097

Abstract

Abstract: Metabolons represent the structural organization of proteins for metabolic or regulatory pathways. Here, the interaction of fumarase FumB, aspartase AspA, and L-tartrate dehydratase TtdAB with the C4-dicarboxylate (C4-DC) transporters DcuA, DcuB, DcuC, and the L-tartrate transporter TtdT of Escherichia coli was tested by a bacterial two-hybrid (BACTH) assay in situ, or by co-chromatography using mSPINE (membrane Streptavidin protein interaction experiment). From the general C4-DC transporters, DcuB interacted with FumB and AspA, DcuA with AspA, whereas DcuC interacted with neither FumB nor AspA. Moreover, TtdT did not interact with TtdAB. The fumB-dcuB, the dcuA-aspA, and the ttdAB-ttdT genes encoding the respective proteins colocalize on the genome and each pair of genes forms cotranscripts, whereas the dcuC gene lies alone. The data suggest the formation of DcuB/FumB and DcuB/AspA metabolons for the uptake of L-malate, or L-aspartate, and their conversion to fumarate for fumarate respiration and excretion of the product succinate. The DcuA/AspA metabolon catalyzes uptake and conversion of L-aspartate to fumarate coupled to succinate excretion. The DcuA/AspA metabolon provides ammonia at the same time for nitrogen assimilation (ammonia shuttle). On the other hand, TtdT and TtdAB are not organized in a metabolon. Reasons for the formation (DcuA/AspA, DcuB/FumB, and DcuB/AspA) or nonformation (DcuC, TtdT, and TtdAB) of metabolons are discussed based on their metabolic roles. Abstract : Experimental measurement for spatial proximity revealed that transporters for general C4 -dicarboxylates, such as L-malate and L-aspartate, form metabolons with cytosolic enzymes, however, no metabolons were observed for noncommon C4 -dicarboxylates.