4ltd | pdb_00004ltd

Crystal structures of NADH:FMN oxidoreductase (EMOB) - apo form

spinqualitylabelsall models 4ltd, resolution 2.19Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4ltd is a 1 chain structure with sequence from EDTA-degrading bacterium BNC1. This structure supersedes the now removed PDB entry 2vzf. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: MSE, PO4, SO4 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function Q9F9T2_9PROT Publication Abstract from PubMed EDTA has become a major organic pollutant in the environment because of its extreme usage and resistance to biodegradation. Recently, two critical enzymes, EDTA monooxygenase (EmoA) and NADH:FMN oxidoreductase (EmoB), belonging to the newly established two-component flavin-diffusible monooxygenase family, were identified in the EDTA degradation pathway in Mesorhizobium sp. BNC1. EmoA is an FMNH2-dependent enzyme that requires EmoB to provide FMNH2 for the conversion of EDTA to ethylenediaminediacetate. To understand the molecular basis of this FMN-mediated reaction, the crystal structures of the apo-form, FMN.FMN complex, and FMN.NADH complex of EmoB were determined at 2.5 angstroms resolution. The structure of EmoB is a homotetramer consisting of four alpha/beta-single-domain monomers of five parallel beta-strands flanked by five alpha-helices, which is quite different from those of other known two-component flavin-diffusible monooxygenase family members, such as PheA2 and HpaC, in terms of both tertiary and quaternary structures. For the first time, the crystal structures of both the FMN.FMN and FMN.NADH complexes of an NADH:FMN oxidoreductase were determined. Two stacked isoalloxazine rings and nicotinamide/isoalloxazine rings were at a proper distance for hydride transfer. The structures indicated a ping-pong reaction mechanism, which was confirmed by activity assays. Thus, the structural data offer detailed mechanistic information for hydride transfer between NADH to an enzyme-bound FMN and between the bound FMNH2 and a diffusible FMN. Crystal structures of NADH:FMN oxidoreductase (EmoB) at different stages of catalysis.,Nissen MS, Youn B, Knowles BD, Ballinger JW, Jun SY, Belchik SM, Xun L, Kang C J Biol Chem. 2008 Oct 17;283(42):28710-20. Epub 2008 Aug 12. PMID:18701448 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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