Arthrobacter nicotinovorans

Baitsch D, C Sandn, R Brandsch, GL Igloi (2001) Gene cluster on pAOl of Arthrobacter nicotinovorans involved in degradation of the plant alkaloid nicotine cloning, purification, and characterization of 2,6-dihydroxypyridine 3-hydrolase. J Bacterid 183 5262-5267. 

Chiribau CB, C Sandu, M Eraaije, E Schiltz, R Bradsch (2004) A novel y-A-methylaminohutyrate demethyl-ating oxidase involved in catabolism of the tobacco alkaloid nicotine by Arthrobacter nicotinovorans pAOl. Eur JBiochem 271 4677-4684. 

The degradation of nicotine has been examined extensively in Arthrobacter nicotinovorans (oxydans) in which it is mediated by a plasmid (Brandsch et al. 1982 Schenk et al. 1998). In strain P34, the hrst metabolite was 6-hydroxynicotine, and experiments with 02 and H2 0 showed that the oxygen in the hydroxyl group was derived from H2O (Hochstein and Dalton 1965). Nicotine dehydrogenase has a molecular mass of 120,000 and contains FAD, Mo, Fe, and acid-labile sulfur (Freudenberg et al. 1988). Degradation involves a series of reactions ... 

Sachelaru P, E Schiltz, GL Igloi, R Brandsch (2005) An a/[5-fold C—C bond hydrolase is involved in a central step of nicotine metabolism by Arthrobacter nicotinovorans. J Bacteriol 187 8516-8519. 

Schenk S, A Hoelz, B Krauss, K Decker (1998) Gene structures and properties of enzymes of the plasmid-encoded nicotine catabolism of Arthrobacter nicotinovorans. J Mol Biol 284 1323-1339. 

Koetter JW, Schulz GE. Crystal structure of 6-hydroxy-D-nicotine oxidase from Arthrobacter nicotinovorans. J. Mol. Biol. 2005 352 418-128. 

Finally, tobacco plants and several fimgi, e,g. Pelliculariaftlamentosa, are able to degrade nicotine to nomicotine. Arthrobacter nicotinovorans and Pseudomonas strains then metabolise this further to 6-hydroxy-3-succinoylpyridine. 

The known monoamine oxidases, including A. niger (MAO-N), are (S)-selective. Recently, an (R)-selective AO from Arthrobacter nicotinovorans was characterized and engineered to broaden its substrate specificity [82]. The crystal structures of MAO-N variants have been solved (Table 7.4). These enzymes have two channels that intersect at the active site and seem to play a role in both the substrate selectivity and enantioselectivity [79a]. 

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