title: Geraniol and geranial dehydrogenases induced in anaerobic monoterpene degradation by Castellaniella defragrans.
abstract: Castellaniella defragrans is a Betaproteobacterium capable of coupling the oxidation of monoterpenes with denitrification. Geraniol dehydrogenase (GeDH) activity was induced during growth with limonene in comparison to growth with acetate. The N-terminal sequence of the purified enzyme directed the cloning of the corresponding open reading frame (ORF), the first bacterial gene for a GeDH (geoA, for geraniol oxidation pathway). The C. defragrans geraniol dehydrogenase is a homodimeric enzyme that affiliates with the zinc-containing benzyl alcohol dehydrogenases in the superfamily of medium-chain-length dehydrogenases/reductases (MDR). The purified enzyme most efficiently catalyzes the oxidation of perillyl alcohol (k(cat)/K(m) = 2.02 × 10(6) M(-1) s(-1)), followed by geraniol (k(cat)/K(m) = 1.57 × 10(6) M(-1) s(-1)). Apparent K(m) values of <10 μM are consistent with an in vivo toxicity of geraniol above 5 μM. In the genetic vicinity of geoA is a putative aldehyde dehydrogenase that was named geoB and identified as a highly abundant protein during growth with phellandrene. Extracts of Escherichia coli expressing geoB demonstrated in vitro a geranial dehydrogenase (GaDH) activity. GaDH activity was independent of coenzyme A. The irreversible formation of geranic acid allows for a metabolic flux from β-myrcene via linalool, geraniol, and geranial to geranic acid.
authors.affiliation: Department of Microbiology, Max Planck Institute for Marine Microbiology, Bremen, Germany.
authors.forename: Frauke
authors.initials: F
authors.lastname: Lüddeke
authors.forename: Annika
authors.initials: A
authors.lastname: Wülfing
authors.forename: Markus
authors.initials: M
authors.lastname: Timke
authors.forename: Frauke
authors.initials: F
authors.lastname: Germer
authors.forename: Johanna
authors.initials: J
authors.lastname: Weber
authors.forename: Aytac
authors.initials: A
authors.lastname: Dikfidan
authors.forename: Tobias
authors.initials: T
authors.lastname: Rahnfeld
authors.forename: Dietmar
authors.initials: D
authors.lastname: Linder
authors.forename: Anke
authors.initials: A
authors.lastname: Meyerdierks
authors.forename: Jens
authors.initials: J
authors.lastname: Harder
mesh_terms: D000080462:Acyclic Monoterpenes; D042401:Alcaligenaceae / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D000429:Alcohol Oxidoreductases / Q000235:genetics / Q000378:metabolism*; D000444:Aldehyde Dehydrogenase / Q000235:genetics / Q000378:metabolism*; D000693:Anaerobiosis; D003470:Culture Media; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial; D008969:Molecular Sequence Data; D039821:Monoterpenes / Q000737:chemistry / Q000378:metabolism*; D017422:Sequence Analysis, DNA; D013729:Terpenes / Q000378:metabolism*
chemical_list: D000080462:Acyclic Monoterpenes; D003470:Culture Media; D039821:Monoterpenes; D013729:Terpenes; D000429:Alcohol Oxidoreductases; D000444:Aldehyde Dehydrogenase; C007836:geraniol; C007076:citral