4pah

HUMAN PHENYLALANINE HYDROXYLASE CATALYTIC DOMAIN DIMER WITH BOUND NOR-ADRENALINE INHIBITOR

spinqualitylabelsall models 4pah, resolution 2.00Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4pah is a 1 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2Å Ligands: FE, LNR Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Disease PH4H_HUMAN Defects in PAH are the cause of phenylketonuria (PKU) [MIM:261600. PKU is an autosomal recessive inborn error of phenylalanine metabolism, due to severe phenylalanine hydroxylase deficiency. It is characterized by blood concentrations of phenylalanine persistently above 1200 mumol (normal concentration 100 mumol) which usually causes mental retardation (unless low phenylalanine diet is introduced early in life). They tend to have light pigmentation, rashes similar to eczema, epilepsy, extreme hyperactivity, psychotic states and an unpleasant 'mousy' odor. Defects in PAH are the cause of non-phenylketonuria hyperphenylalaninemia (Non-PKU HPA) [MIM:261600. Non-PKU HPA is a mild form of phenylalanine hydroxylase deficiency characterized by phenylalanine levels persistently below 600 mumol, which allows normal intellectual and behavioral development without treatment. Non-PKU HPA is usually caused by the combined effect of a mild hyperphenylalaninemia mutation and a severe one. Defects in PAH are the cause of hyperphenylalaninemia (HPA) [MIM:261600. HPA is the mildest form of phenylalanine hydroxylase deficiency. Function PH4H_HUMAN 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 The aromatic amino acid hydroxylases represent a superfamily of structurally and functionally closely related enzymes, one of those functions being reversible inhibition by catechol derivatives. Here we present the crystal structure of the dimeric catalytic domain (residues 117-424) of human phenylalanine hydroxylase (hPheOH), cocrystallized with various potent and well-known catechol inhibitors and refined at a resolution of 2.0 A. The catechols bind by bidentate coordination to each iron in both subunits of the dimer through the catechol hydroxyl groups, forming a blue-green colored ligand-to-metal charge-transfer complex. In addition, Glu330 and Tyr325 are identified as determinant residues in the recognition of the inhibitors. In particular, the interaction with Glu330 conforms to the structural explanation for the pH dependence of catecholamine binding to PheOH, with a pKa value of 5.1 (20 degreesC). The overall structure of the catechol-bound enzyme is very similar to that of the uncomplexed enzyme (rms difference of 0.2 A for the Calpha atoms). Most striking is the replacement of two iron-bound water molecules with catechol hydroxyl groups. This change is consistent with a change in the ligand field symmetry of the high-spin (S = 5/2) Fe(III) from a rhombic to a nearly axial ligand field symmetry as seen upon noradrenaline binding using EPR spectroscopy [Martinez, A., Andersson, K. K., Haavik, J., and Flatmark, T. (1991) Eur. J. Biochem. 198, 675-682]. Crystallographic comparison with the structurally related rat tyrosine hydroxylase binary complex with the oxidized cofactor 7,8-dihydrobiopterin revealed overlapping binding sites for the catechols and the cofactor, compatible with a competitive type of inhibition of the catechols versus BH4. The comparison demonstrates some structural differences at the active site as the potential basis for the different substrate specificity of the two enzymes. Crystallographic analysis of the human phenylalanine hydroxylase catalytic domain with bound catechol inhibitors at 2.0 A resolution.,Erlandsen H, Flatmark T, Stevens RC, Hough E Biochemistry. 1998 Nov 10;37(45):15638-46. PMID:9843368 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Hydroxylases 3D structures

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