1pjq

Structure and function of CysG, the multifunctional methyltransferase/dehydrogenase/ferrochelatase for siroheme synthesis

spinqualitylabelsall models 1pjq, resolution 2.21Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1pjq is a 2 chain structure with sequence from Salmonella enterica subsp. enterica serovar Typhimurium. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.21Å Ligands: ACT, PGE, SAH, SEP Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT 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 Sulfur metabolism depends on the iron-containing porphinoid siroheme. In Salmonella enterica, the S-adenosyl-L-methionine (SAM)-dependent bismethyltransferase, dehydrogenase and ferrochelatase, CysG, synthesizes siroheme from uroporphyrinogen III (uro'gen III). The reactions mediated by CysG encompass two branchpoint intermediates in tetrapyrrole biosynthesis, diverting flux first from protoporphyrin IX biosynthesis and then from cobalamin (vitamin B(12)) biosynthesis. We determined the first structure of this multifunctional siroheme synthase by X-ray crystallography. CysG is a homodimeric gene fusion product containing two structurally independent modules: a bismethyltransferase and a dual-function dehydrogenase-chelatase. The methyltransferase active site is a deep groove with a hydrophobic patch surrounded by hydrogen bond donors. This asymmetric arrangement of amino acids may be important in directing substrate binding. Notably, our structure shows that CysG is a phosphoprotein. From mutational analysis of the post-translationally modified serine, we suggest a conserved role for phosphorylation in inhibiting dehydrogenase activity and modulating metabolic flux between siroheme and cobalamin pathways. CysG structure reveals tetrapyrrole-binding features and novel regulation of siroheme biosynthesis.,Stroupe ME, Leech HK, Daniels DS, Warren MJ, Getzoff ED Nat Struct Biol. 2003 Dec;10(12):1064-73. Epub 2003 Nov 2. PMID:14595395 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Siroheme synthase

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