Mimosine binding domain of ABC-type transporter MidA and similar proteins; the type 2 periplasmic binding protein fold.
This subgroup includes the periplasmic binding component of ABC transporter involved in uptake of mimosine MidA and its similar proteins. This periplasmic binding domain belongs to the type 2 periplasmic-binding fold protein (PBP2) superfamily, whose members are involved in chemotaxis and uptake of nutrients and other small molecules from the extracellular space as a primary receptor. PBP2 typically comprises 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. 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 receptor cytoplasmically-located ATPase domains. This interaction triggers the ligand translocation across the cytoplasmic membrane energized by ATP hydrolysis.
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