2ybo

The x-ray structure of the SAM-dependent uroporphyrinogen III methyltransferase NirE from Pseudomonas aeruginosa in complex with SAH

spinqualitylabelsall models 2ybo, resolution 2.00Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2ybo is a 1 chain structure with sequence from Pseudomonas aeruginosa PAO1. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2Å Ligands: SAH Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function P95417_PSEAI Publication Abstract from PubMed During the biosynthesis of heme d(1), the essential cofactor of cytochrome cd(1) nitrite reductase, the NirE protein catalyzes the methylation of uroporphyrinogen III to precorrin-2 using S-adenosyl-L-methionine (SAM) as the methyl group donor. The crystal structure of Pseudomonas aeruginosa NirE in complex with its substrate uroporphyrinogen III and the reaction by-product S-adenosyl-L-homocysteine (SAH) was solved to 2.0 A resolution. This represents the first enzyme-substrate complex structure for a SAM-dependent uroporphyrinogen III methyltransferase. The large substrate binds on top of the SAH in a "puckered" conformation in which the two pyrrole rings facing each other point into the same direction either upward or downward. Three arginine residues, a histidine, and a methionine are involved in the coordination of uroporphyrinogen III. Through site-directed mutagenesis of the nirE gene and biochemical characterization of the corresponding NirE variants the amino acid residues Arg-111, Glu-114, and Arg-149 were identified to be involved in NirE catalysis. Based on our structural and biochemical findings, we propose a potential catalytic mechanism for NirE in which the methyl transfer reaction is initiated by an arginine catalyzed proton abstraction from the C-20 position of the substrate. Crystal structure of the heme d1 biosynthesis enzyme NirE in complex with its substrate reveals new insights into the catalytic mechanism of S-adenosyl-L-methionine-dependent uroporphyrinogen III methyltransferases.,Storbeck S, Saha S, Krausze J, Klink BU, Heinz DW, Layer G J Biol Chem. 2011 Jul 29;286(30):26754-67. Epub 2011 May 31. PMID:21632530 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also SAM-dependent methyltrasferase 3D structures

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