Abstract
The first structure of nicotine oxidoreductase (NicA2) was determined by X-ray crystallography. Pseudomonas putida has evolved nicotine-degrading activity to provide a source of carbon and nitrogen. The structure establishes NicA2 as a member of the monoamine oxidase family. Residues 1-50 are disordered and may play a role in localization. The nicotine-binding site proximal to the isoalloxazine ring of flavin shows an unusual composition of the classical aromatic cage (W427 and N462). The active site architecture is consistent with the proposed binding of the deprotonated form of the substrate and the flavin-dependent oxidation of the pyrrolidone C-N bond followed by nonenzymatic hydrolysis.
MeSH terms
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Amino Acid Sequence
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Bacterial Proteins / chemistry
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Bacterial Proteins / metabolism*
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Binding Sites / genetics
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Catalytic Domain
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Crystallography, X-Ray
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Dinitrocresols / chemistry
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Dinitrocresols / metabolism
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Flavins / chemistry
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Flavins / metabolism
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Models, Chemical
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Models, Molecular
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Molecular Structure
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Monoamine Oxidase / chemistry
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Monoamine Oxidase / genetics
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Monoamine Oxidase / metabolism
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Nicotine / chemistry
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Nicotine / metabolism*
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Oxidation-Reduction
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Oxidoreductases / chemistry
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Oxidoreductases / genetics
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Oxidoreductases / metabolism*
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Protein Domains
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Protein Structure, Secondary
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Pseudomonas putida / enzymology*
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Pseudomonas putida / genetics
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Pseudomonas putida / metabolism
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Sequence Homology, Amino Acid
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Substrate Specificity
Substances
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Bacterial Proteins
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Dinitrocresols
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Flavins
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4,6-dinitro-o-cresol
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isoalloxazine
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Nicotine
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Oxidoreductases
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Monoamine Oxidase