4jpx | pdb_00004jpx

Crystal structure of phenylalanine hydroxylase S203P mutant from Chromobacterium violaceum

spinqualitylabelsall models 4jpx, resolution 1.55Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4jpx is a 1 chain structure with sequence from Chromobacterium violaceum ATCC 12472. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.55Å Ligands: CO, PHE Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function PH4H_CHRVO Publication Abstract from PubMed Phenylalanine hydroxylase (PAH) is a non-heme iron enzyme that catalyzes oxidation of phenylalanine to tyrosine, a reaction that must be kept under tight regulatory control. Mammalian PAH has a regulatory domain in which binding of the substrate leads to allosteric activation of the enzyme. However, the existence of PAH regulation in evolutionarily distant organisms, for example some bacteria in which it occurs, has so far been underappreciated. In an attempt to crystallographically characterize substrate binding by PAH from Chromobacterium violaceum, a single-domain monomeric enzyme, electron density for phenylalanine was observed at a distal site 15.7 A from the active site. Isothermal titration calorimetry (ITC) experiments revealed a dissociation constant of 24 +/- 1.1 muM for phenylalanine. Under the same conditions, ITC revealed no detectable binding for alanine, tyrosine, or isoleucine, indicating the distal site may be selective for phenylalanine. Point mutations of amino acid residues in the distal site that contact phenylalanine (F258A, Y155A, T254A) led to impaired binding, consistent with the presence of distal site binding in solution. Although kinetic analysis revealed that the distal site mutants suffer discernible loss of their catalytic activity, X-ray crystallographic analysis of Y155A and F258A, the two mutants with the most noticeable decrease in activity, revealed no discernible change in the structure of their active sites, suggesting that the effect of distal binding may result from protein dynamics in solution. An additional substrate binding site in a bacterial phenylalanine hydroxylase.,Ronau JA, Paul LN, Fuchs JE, Corn IR, Wagner KT, Liedl KR, Abu-Omar MM, Das C Eur Biophys J. 2013 Jul 17. PMID:23860686 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Hydroxylases 3D structures

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