5kow

Structure of rifampicin monooxygenase

spinqualitylabelsall models 5kow, resolution 2.10Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 5kow is a 1 chain structure with sequence from "actinomyces_bovis_farcinicus"_gasperini_1894 "actinomyces bovis farcinicus" gasperini 1894. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: ACT, FAD Related: 5kox Gene: pcpB_1, ERS450000_00511 ("Actinomyces bovis farcinicus" Gasperini 1894) Activity: Pentachlorophenol monooxygenase, with EC number 1.14.13.50 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed Rifampicin monooxygenase (RIFMO) catalyzes the N-hydroxylation of the natural product antibiotic rifampicin (RIF) to 2'-N-hydroxy-4-oxo-rifampicin, a metabolite with much lower antimicrobial activity. RIFMO shares moderate sequence similarity with well-characterized flavoprotein monooxygenases, but the protein has not been isolated and characterized at the molecular level. Herein, we report crystal structures of RIFMO from Nocardia farcinica, the determination of the oligomeric state in solution with small-angle X-ray scattering, and the spectrophotometric characterization of substrate binding. The structure identifies RIFMO as a class A flavoprotein monooxygenase and is similar in fold and quaternary structure to MtmOIV and OxyS, which are enzymes in the mithramycin and oxytetracycline biosynthetic pathways, respectively. RIFMO is distinguished from other class A flavoprotein monooxygenases by its unique middle domain, which is involved in binding RIF. Small-angle X-ray scattering analysis shows that RIFMO dimerizes via the FAD-binding domain to form a bell-shaped homodimer in solution with a maximal dimension of 110 A. RIF binding was monitored using absorbance at 525 nm to determine a dissociation constant of 13 muM. Steady-state oxygen consumption assays show that NADPH efficiently reduces the FAD only when RIF is present, implying that RIF binds before NADPH in the catalytic scheme. The 1.8 A resolution structure of RIFMO complexed with RIF represents the pre-catalytic conformation that occurs prior to formation of the ternary E-RIF-NADPH complex. The RIF naphthoquinone blocks access to the FAD N5 atom, implying that large conformational changes are required for NADPH to reduce the FAD. A model for these conformational changes is proposed. The Structure of the Antibiotic Deactivating, N-hydroxylating Rifampicin Monooxygenase.,Liu LK, Abdelwahab H, Martin Del Campo JS, Mehra-Chaudhary R, Sobrado P, Tanner JJ J Biol Chem. 2016 Aug 24. pii: jbc.M116.745315. PMID:27557658 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Monooxygenase 3D structures

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