Maltose transport through the inner membrane of em E coli em

Abstract

The maltose transport complex of E.coli is one of the most well-characterized members of the ATP-Binding Cassette (ABC) protein superfamily. ABC proteins represent the largest superfamily of transmembrane proteins in prokaryotes and eukaryotes, performing diverse functions from ion transport by the cystic fibrosis transmembrane regulator to multiple drug efflux by the P-glycoprotein transporter and sugar transport by the maltose transporter. Characterization of the mechanism of transport for ABC transporters is currently being investigated both biochemically and structurally, however some uncertainty remains as to how the individual subunits of these multisubunit transporters interact. This review discusses the current knowledge of the mechanism of maltose transport, as it relates to the ABC superfamily of transporters as a whole.

How Phosphotransferase System-Related Protein Phosphorylation Regulates Carbohydrate Metabolism in Bacteria

“…Maltose uptake in E. coli requires the malE-encoded periplasmic maltose binding protein and the multisubunit ABC transporter MalFGK 2 (72,226,447). The soluble MalK subunits are tightly associated with the two permease subunits MalF and MalG (354,580).…”

“…Binding of maltose-carrying maltose binding protein to MalFGK 2 stimulates ATP hydrolysis by MalK and therefore maltose transport (118,161,187). Stimulation of ATP hydrolysis is cooperative, suggesting that the MalK subunits interact with each other (159,160,226). MalK possesses an N-terminal ATPase domain (present in all ATP-binding proteins of ABC transporters) and, in certain bacteria including E. coli and S. enterica serovar Typhimurium, a specific C-terminal regulatory domain (66,187,782,828).…”

Lessons From Lactose Permease

“…The glucose PTS also plays a key role in the phenomenon of catabolite repression. (b) Transporters of the ATP-binding cassette (ABC) system (19) are found in both prokaryotes and eukaryotes and have a common global organization with two integral membrane components, each of which has multiple-transmembrane helices, and two cytoplasmic components, each of which has one ATP-binding cassette (19,61). ABC transporters may be in the form of a monomer or various combinations of fused components.…”

Identification of Putative Substrates for the Periplasmic Chaperone YfgM in Escherichia coli Using Quantitative Proteomics

“…2A). Again, the list included proteins involved in maltose metabolism (MalE) (21), survival during gastrointestinal stresses (HdeA, HdeB, GrcA, and TdcB) (23,24) and growth under anaerobic conditions (FrdA and FrdB) (30). Six of the proteins that were lower in abundance in this experiment are localized in the envelope, thus they could be potential substrates for YfgM.…”

“…2A). Some of these could be grouped according to their biological function, for example proteins required for maltose metabolism (MalF, MalP, and MalQ) (21), anaerobic growth with dimethyl sulfoxide (DmsA and DmsB) (22), and survival during gastrointestinal stresses such as low pH and exposure to bile salts (TdcB, TdcC, TdcD, TdcE, Cfa, CadA, GrcA, and HdeB) (23,24). Around a third of the proteins were localized to the cell envelope (as noted by (25,26)) and could be potential substrates of YfgM.…”