2jbw

Crystal Structure of the 2,6-dihydroxy-pseudo-oxynicotine Hydrolase.

spinqualitylabelsall models 2jbw, resolution 2.10Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2jbw is a 4 chain structure with sequence from Paenarthrobacter nicotinovorans. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.1Å Ligands: MSE, NA Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function DHPON_PAENI L-nicotine is used as a growth substrate. Plays a role in nicotine catabolism by cleaving a C-C bond in 2,6-dihydroxypseudooxynicotine. 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 enzyme 2,6-dihydroxy-pseudo-oxynicotine hydrolase from the nicotine-degradation pathway of Arthrobacter nicotinovorans was crystallized and the structure was determined by an X-ray diffraction analysis at 2.1 A resolution. The enzyme belongs to the alpha/beta-hydrolase family as derived from the chain-fold and from the presence of a catalytic triad with its oxyanion hole at the common position. This relationship assigns a pocket lined by the catalytic triad as the active center. The asymmetric unit contains two C(2)-symmetric dimer molecules, each adopting a specific conformation. One dimer forms a more spacious active center pocket and the other a smaller one, suggesting an induced-fit. All of the currently established C-C bond cleaving alpha/beta-hydrolases are from bacterial meta-cleavage pathways for the degradation of aromatic compounds and cover their active center with a 40 residue lid placed between two adjacent strands of the beta-sheet. In contrast, the reported enzyme shields its active center with a 110 residue N-terminal domain, which is absent in the meta-cleavage hydrolases. Since neither the substrate nor an analogue could be bound in the crystals, the substrate was modeled into the active center using the oxyanion hole as a geometric constraint. The model was supported by enzymatic activity data of 11 point mutants and by the two dimer conformations suggesting an induced-fit. Moreover, the model assigned a major role for the large N-terminal domain that is specific to the reported enzyme. The proposal is consistent with the known data for the meta-cleavage hydrolases although it differs in that the reaction does not release alkenes but a hetero-aromatic compound in a retro-Friedel-Crafts acylation. Because the hydrolytic water molecule can be assigned to a geometrically suitable site that can be occupied in the presence of the substrate, the catalytic triad may not form a covalent acyl-enzyme intermediate but merely support a direct hydrolysis. Structure and action of a C-C bond cleaving alpha/beta-hydrolase involved in nicotine degradation.,Schleberger C, Sachelaru P, Brandsch R, Schulz GE J Mol Biol. 2007 Mar 23;367(2):409-18. Epub 2006 Dec 30. PMID:17275835 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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