4hsj

1.88 angstrom x-ray crystal structure of piconlinic-bound 3-hydroxyanthranilate-3,4-dioxygenase

spinqualitylabelsall models 4hsj, resolution 1.88Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4hsj is a 1 chain structure with sequence from Cupmc. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: 6PC, FE2 Related: 4hsk, 4hsl, 4hsm Gene: nbaC, Ralstonia metallidurans, Rmet_5193 (CUPMC) Activity: 3-hydroxyanthranilate 3,4-dioxygenase, with EC number 1.13.11.6 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [3HAO_RALME] Catalyzes the oxidative ring opening of 3-hydroxyanthranilate to 2-amino-3-carboxymuconate semialdehyde, which spontaneously cyclizes to quinolinate. Publication Abstract from PubMed The rubredoxin motif is present in over 74,000 protein sequences and 2,000 structures, but few have known functions. A secondary, non-catalytic, rubredoxin-like iron site is conserved in 3-hydroxyanthranilate 3,4-dioxygenase (HAO), from single cellular sources but not multicellular sources. Through the population of the two metal binding sites with various metals in bacterial HAO, the structural and functional relationship of the rubredoxin-like site was investigated using kinetic, spectroscopic, crystallographic, and computational approaches. It is shown that the first metal presented preferentially binds to the catalytic site rather than the rubredoxin-like site, which selectively binds iron when the catalytic site is occupied. Furthermore, an iron ion bound to the rubredoxin-like site is readily delivered to an empty catalytic site of metal-free HAO via an intermolecular transfer mechanism. Through the use of metal analysis and catalytic activity measurements, we show that a downstream metabolic intermediate can selectively remove the catalytic iron. As the prokaryotic HAO is often crucial for cell survival, there is a need for ensuring its activity. These results suggest that the rubredoxin-like site is a possible auxiliary iron source to the catalytic center when it is lost during catalysis in a pathway with metabolic intermediates of metal-chelating properties. A spare tire concept is proposed based on this biochemical study, and this concept opens up a potentially new functional paradigm for iron-sulfur centers in iron-dependent enzymes as transient iron binding and shuttling sites to ensure full metal loading of the catalytic site. An Iron Reservoir to the Catalytic Metal: THE RUBREDOXIN IRON IN AN EXTRADIOL DIOXYGENASE.,Liu F, Geng J, Gumpper RH, Barman A, Davis I, Ozarowski A, Hamelberg D, Liu A J Biol Chem. 2015 Jun 19;290(25):15621-34. doi: 10.1074/jbc.M115.650259. Epub, 2015 Apr 27. PMID:25918158 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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