1r9q

structure analysis of ProX in complex with proline betaine

spinqualitylabelsall models 1r9q, resolution 2.05Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1r9q is a 1 chain structure with sequence from Escherichia coli. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.05Å Ligands: PBE, UNX Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function PROX_ECOLI Member of a multicomponent binding-protein-dependent transport system (the ProU transporter) which serves as the glycine betaine/L-proline transporter. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed Compatible solutes such as glycine betaine and proline betaine are accumulated to exceedingly high intracellular levels by many organisms in response to high osmolarity to offset the loss of cell water. They are excluded from the immediate hydration shell of proteins and thereby stabilize their native structure. Despite their exclusion from protein surfaces, the periplasmic ligand-binding protein ProX from the Escherichia coli ATP-binding cassette transport system ProU binds the compatible solutes glycine betaine and proline betaine with high affinity and specificity. To understand the mechanism of compatible solute binding, we determined the high resolution structure of ProX in complex with its ligands glycine betaine and proline betaine. This crystallographic study revealed that cation-pi interactions between the positive charge of the quaternary amine of the ligands and three tryptophan residues forming a rectangular aromatic box are the key determinants of the high affinity binding of compatible solutes by ProX. The structural analysis was combined with site-directed mutagenesis of the ligand binding pocket to estimate the contributions of the tryptophan residues involved in binding. Cation-pi interactions as determinants for binding of the compatible solutes glycine betaine and proline betaine by the periplasmic ligand-binding protein ProX from Escherichia coli.,Schiefner A, Breed J, Bosser L, Kneip S, Gade J, Holtmann G, Diederichs K, Welte W, Bremer E J Biol Chem. 2004 Feb 13;279(7):5588-96. Epub 2003 Nov 11. PMID:14612446 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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