Escherichia coli maltose-binding protein (MBP) (MBP)

The Maltose-binding protein (MBP) is a 42.5 kDa periplasmic protein in Escherichia coli, encoded by the malE gene, that serves as a primary receptor for the uptake of maltose and maltodextrins (UniProt: P0AEX9). It is a member of the periplasmic-binding protein (PBP) superfamily and operates via a Venus flytrap mechanism, where ligand binding induces a transition from an open to a closed conformation (PubMed: 10411885). This closed conformation is recognized by the MalFGK2 ABC transporter, facilitating the movement of sugars into the cell. Beyond its transport role, MBP also functions as a chemoreceptor for chemotaxis, interacting with the Tar protein to direct the bacteria toward higher concentrations of maltose (PubMed: 6250371). In biotechnology, MBP is one of the most common fusion tags used to enhance the solubility of recombinant proteins and simplify purification through amylose affinity chromatography (PubMed: 15210514). Although not a traditional target for clinical drugs, its role in bacterial survival and its utility in protein engineering make it a cornerstone of molecular biology research.

Other names

MalEMaltose/maltodextrin-binding proteinPeriplasmic maltose-binding proteinMaltodextrin-binding protein

MBP captures maltose or maltodextrins in the periplasm and undergoes a large-scale conformational change from an open to a closed state, which then interacts with the MalFGK2 complex to stimulate ATP hydrolysis and substrate translocation (PubMed: 10411885).