2azn

X-RAY Structure of 2,5-diamino-6-ribosylamino-4(3h)-pyrimidinone 5-phosphate reductase

spinqualitylabelsall models 2azn, resolution 2.70Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2azn is a 6 chain structure with sequence from Methanocaldococcus jannaschii. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: EPE, MA5, NAP NonStd Res: MSE Activity: 5-amino-6-(5-phosphoribosylamino)uracil reductase, with EC number 1.1.1.193 Resources: FirstGlance, OCA, RCSB, PDBsum Function [RIB7_METJA] Catalyzes an early step in riboflavin biosynthesis, the NAD(P)H-dependent reduction of the ribose side chain of 2,5-diamino-6-ribosylamino-4(3H)-pyrimidinone 5'-phosphate, yielding 2,5-diamino-6-ribitylamino-4(3H)-pyrimidinone 5'-phosphate. The beta anomer is the authentic substrate, and the alpha anomer can serve as substrate subsequent to spontaneous anomerization. NADPH and NADH function equally well as the reductants. Does not catalyze the reduction of 5-amino-6-(5-phospho-D-ribosylamino)uracil to 5-amino-6-(5-phospho-D-ribitylamino)uracil. 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 pyrimidine reductase of the riboflavin biosynthetic pathway (MjaRED) specified by the open reading frame MJ0671 of Methanocaldococcus jannaschii was expressed in Escherichia coli using a synthetic gene. The synthetic open reading frame that was optimized for expression in E. coli directed the synthesis of abundant amounts of the enzyme with an apparent subunit mass of 25 kDa. The enzyme was purified to apparent homogeneity and was shown to catalyze the conversion of 2,5-diamino-6-ribosylamino-4(3H)-pyrimidinone 5'-phosphate into 2,5-diamino-6-ribitylamino-4(3H)-pyrimidinone 5'-phosphate at a rate of 0.8 micromol min(-1) mg(-1) at pH 8.0 and at 30 degrees C. The protein is a homodimer as shown by sedimentation equilibrium analysis and sediments at an apparent velocity of 3.5 S. The structure of the enzyme in complex with the cofactor nicotinamide adenine dinucleotide phosphate was determined by X-ray crystallography at a resolution of 2.5 Angstroms. The folding pattern resembles that of dihydrofolate reductase with the Thermotoga maritima ortholog as the most similar structure. The substrate, 2,5-diamino-6-ribosylamino-4(3H)-pyrimidinone 5'-phosphate, was modeled into the putative active site. The model suggests the transfer of the pro-R hydrogen of C-4 of NADPH to C-1' of the substrate. Biosynthesis of riboflavin: structure and properties of 2,5-diamino-6-ribosylamino-4(3H)-pyrimidinone 5'-phosphate reductase of Methanocaldococcus jannaschii.,Chatwell L, Krojer T, Fidler A, Romisch W, Eisenreich W, Bacher A, Huber R, Fischer M J Mol Biol. 2006 Jun 23;359(5):1334-51. Epub 2006 May 6. PMID:16730025 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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