title: Differential degradation of bicyclics with aromatic and alicyclic rings by Rhodococcus sp. strain DK17.
abstract: The metabolically versatile Rhodococcus sp. strain DK17 is able to grow on tetralin and indan but cannot use their respective desaturated counterparts, 1,2-dihydronaphthalene and indene, as sole carbon and energy sources. Metabolite analyses by gas chromatography-mass spectrometry and nuclear magnetic resonance spectrometry clearly show that (i) the meta-cleavage dioxygenase mutant strain DK180 accumulates 5,6,7,8-tetrahydro-1,2-naphthalene diol, 1,2-indene diol, and 3,4-dihydro-naphthalene-1,2-diol from tetralin, indene, and 1,2-dihydronaphthalene, respectively, and (ii) when expressed in Escherichia coli, the DK17 o-xylene dioxygenase transforms tetralin, indene, and 1,2-dihydronaphthalene into tetralin cis-dihydrodiol, indan-1,2-diol, and cis-1,2-dihydroxy-1,2,3,4-tetrahydronaphthalene, respectively. Tetralin, which is activated by aromatic hydroxylation, is degraded successfully via the ring cleavage pathway to support growth of DK17. Indene and 1,2-dihydronaphthalene do not serve as growth substrates because DK17 hydroxylates them on the alicyclic ring and further metabolism results in a dead-end metabolite. This study reveals that aromatic hydroxylation is a prerequisite for proper degradation of bicyclics with aromatic and alicyclic rings by DK17 and confirms the unique ability of the DK17 o-xylene dioxygenase to perform distinct regioselective hydroxylations.
authors.affiliation: Division of Life Sciences, Korea Polar Research Institute, Incheon 406-840, Korea.
authors.forename: Dockyu
authors.initials: D
authors.lastname: Kim
authors.forename: Miyoun
authors.initials: M
authors.lastname: Yoo
authors.forename: Ki Young
authors.initials: KY
authors.lastname: Choi
authors.forename: Beom Sik
authors.initials: BS
authors.lastname: Kang
authors.forename: Tai Kyoung
authors.initials: TK
authors.lastname: Kim
authors.forename: Soon Gyu
authors.initials: SG
authors.lastname: Hong
authors.forename: Gerben J
authors.initials: GJ
authors.lastname: Zylstra
authors.forename: Eungbin
authors.initials: E
authors.lastname: Kim
mesh_terms: D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000378:metabolism*; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D008401:Gas Chromatography-Mass Spectrometry; D015870:Gene Expression; D006840:Hydrocarbons, Alicyclic / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D011084:Polycyclic Aromatic Hydrocarbons / Q000378:metabolism*; D012240:Rhodococcus / Q000737:chemistry / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*
chemical_list: D019086:Bridged Bicyclo Compounds, Heterocyclic; D006840:Hydrocarbons, Alicyclic; D011084:Polycyclic Aromatic Hydrocarbons