7f6f

Crystal structure of metal-citrate-binding protein (MctA) of ABC transporter endogenously bound to Mg2+-citrate complex (Form II)

spinqualitylabelsall models 7f6f, resolution 2.10Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 7f6f is a 2 chain structure with sequence from Thermus thermophilus HB8. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.1Å Ligands: CIT, CO2, EDO, MG, PEG, PGO Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function Q53VZ2_THET8 Publication Abstract from PubMed More than one third of proteins require metal ions to accomplish their functions, making them obligatory for the growth and survival of microorganisms in varying environmental niches. In prokaryotes, besides their involvement in various cellular and physiological processes, metal ions stimulate the uptake of citrate molecules. Citrate is a source of carbon and energy and is reported to be transported by secondary transporters. In Gram-positive bacteria, citrate molecules are transported in complex with divalent metal ions, whereas in Gram-negative bacteria they are translocated by Na(+)/citrate symporters. In this study, the presence of a novel divalent-metal-ion-complexed citrate-uptake system that belongs to the primary active ABC transporter superfamily is reported. For uptake, the metal-ion-complexed citrate molecules are sequestered by substrate-binding proteins (SBPs) and transferred to transmembrane domains for their transport. This study reports crystal structures of an Mg(2+)-citrate-binding protein (MctA) from the Gram-negative thermophilic bacterium Thermus thermophilus HB8 in both apo and holo forms in the resolution range 1.63-2.50 A. Despite binding various divalent metal ions, MctA possesses the coordination geometry to bind its physiological metal ion, Mg(2+). The results also suggest an extended subclassification of cluster D SBPs, which are known to bind and transport divalent-metal-ion-complexed citrate molecules. Comparative assessment of the open and closed conformations of the wild-type and mutant MctA proteins suggests a gating mechanism of ligand entry following an `asymmetric domain movement' of the N-terminal domain for substrate binding. Structural and thermodynamic insights into a novel Mg(2+)-citrate-binding protein from the ABC transporter superfamily.,Mandal SK, Kanaujia SP Acta Crystallogr D Struct Biol. 2021 Dec 1;77(Pt 12):1516-1534. doi:, 10.1107/S2059798321010457. Epub 2021 Nov 11. PMID:34866608 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also ABC transporter 3D structures

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