The periplasmic binding component of ABC tansport system specific for maltose; possess the type 2 periplasmic binidng fold.
This group includes the periplasmic maltose-binding protein of an ATP-binding cassette transporter. Maltose is a disaccharide formed from two units of glucose. Members of this group belong to the type 2 periplasmic-binding fold superfamily. PBP2 is comprised of two globular subdomains connected by a flexible hinge and bind their ligand in the cleft between these domains in a manner resembling a Venus flytrap. The majority of PBP2 proteins function in the uptake of small soluble substrates in eubacteria and archaea. After binding their specific ligand with high affinity, they can interact with a cognate membrane transport complex comprised of two integral membrane domains and two cytoplasmically located ATPase domains. This interaction triggers the ligand translocation across the cytoplasmic membrane energized by ATP hydrolysis.
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