6cva

Crystal structure of the N. meningitides methionine-binding protein in its substrate-free conformation

spinqualitylabelsall models 6cva, resolution 1.56Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 6cva is a 1 chain structure with sequence from Neisseria meningitidis. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.559Å Ligands: MSE Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function Q9JPG4_NEIME Publication Abstract from PubMed The bacterial periplasmic methionine-binding protein MetQ is involved in the import of methionine by the cognate MetNI methionine ABC transporter. The MetNIQ system is one of the few members of the ABC importer family that has been structurally characterized in multiple conformational states. Critical missing elements in the structural analysis of MetNIQ are the structure of the substrate-free form of MetQ, and detailing how MetQ binds multiple methionine derivatives, including both L- and D-methionine isomers. In this study, we report the structures of the Neisseria meningitides MetQ in substrate-free form and in complexes with L-methionine and with D-methionine, along with the associated binding constants determined by isothermal titration calorimetry. Structures of the substrate-free (N238A) and substrate-bound N. meningitides MetQ are related by a "Venus-fly trap" hinge-type movement of the two domains accompanying methionine binding and dissociation. L-methionine and D-methionine bind to the same site on MetQ, and this study emphasizes the important role of asparagine 238 in ligand binding and affinity. A thermodynamic analysis demonstrates that ligand-free MetQ associates with the ATP bound form of MetNI ~40 times more tightly than does liganded MetQ, consistent with the necessity of dissociating methionine from MetQ for transport to occur. This article is protected by copyright. All rights reserved. Structures of the Neisseria meningitides methionine-binding protein MetQ in substrate-free form and bound to L- and D-methionine isomers.,Nguyen PT, Lai JY, Kaiser JT, Rees DC Protein Sci. 2019 Jul 26. doi: 10.1002/pro.3694. PMID:31348565 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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