title: Permissivity of the biphenyl-specific aerobic bacterial metabolic pathway towards analogues with various steric requirements.
abstract: It has repeatedly been shown that aryl-hydroxylating dioxygenases do not possess a very high substrate specificity. To gain more insight into this phenomenon, we examined two powerful biphenyl dioxygenases, the well-known wild-type enzyme from Burkholderia xenovorans LB400 (BphA-LB400) and a hybrid enzyme, based on a dioxygenase from Pseudomonas sp. B4-Magdeburg (BphA-B4h), for their abilities to dioxygenate a selection of eight biphenyl analogues in which the second aromatic ring was replaced by aliphatic as well as aliphatic/aromatic moieties, reflecting a variety of steric requirements. Interestingly, both enzymes were able to catalyse transformation of almost all of these compounds. While the products formed were identical, major differences were observed in transformation rates. In most cases, BphA-B4h proved to be a significantly more powerful catalyst than BphA-LB400. NMR characterization of the reaction products showed that the metabolite obtained from biphenylene underwent angular dioxygenation, whereas all other compounds were subject to lateral dioxygenation at ortho and meta carbons. Subsequent growth studies revealed that both dioxygenase source strains were able to utilize several of the biphenyl analogues as sole sources of carbon and energy. Therefore, prototype BphBCD enzymes of the biphenyl degradative pathway were examined for their ability to further catabolize the lateral dioxygenation products. All of the ortho- and meta-hydroxylated compounds were converted to acids, showing that this pathway is quite permissive, enabling catalysis of the turnover of a fairly wide variety of metabolites.
authors: Department of Chemical Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany.
authors: Heike
authors: H
authors: Overwin
authors: Division of Microbiology, Helmholtz Centre for Infection Research, Braunschweig, Germany.
authors: Christine
authors: C
authors: Standfuß-Gabisch
authors: Laboratorio de Microbiología Molecular y Biotecnología Ambiental, Departamento de Química, Universidad Técnica Federico Santa María, Valparaíso, Chile.
authors: Myriam
authors: M
authors: González
authors: Laboratorio de Microbiología Molecular y Biotecnología Ambiental, Departamento de Química, Universidad Técnica Federico Santa María, Valparaíso, Chile.
authors: Valentina
authors: V
authors: Méndez
authors: Laboratorio de Microbiología Molecular y Biotecnología Ambiental, Departamento de Química, Universidad Técnica Federico Santa María, Valparaíso, Chile.
authors: Michael
authors: M
authors: Seeger
authors: Department of Structure and Function of Proteins, Helmholtz Centre for Infection Research, Braunschweig, Germany.
authors: Joachim
authors: J
authors: Reichelt
authors: Department of Molecular Structural Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany.
authors: Victor
authors: V
authors: Wray
authors: Department of Chemical Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany.|Division of Microbiology, Helmholtz Centre for Infection Research, Braunschweig, Germany.
authors: Bernd
authors: B
authors: Hofer
mesh_terms: D001420:Bacteria, Aerobic / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D001713:Biphenyl Compounds / Q000378:metabolism*; D049308:Dioxygenases / Q000378:metabolism; D008401:Gas Chromatography-Mass Spectrometry; D006841:Hydrocarbons, Aromatic / Q000378:metabolism; D006868:Hydrolysis; D053858:Metabolic Networks and Pathways; D019906:Nuclear Magnetic Resonance, Biomolecular; D010084:Oxidation-Reduction
chemical_list: D001713:Biphenyl Compounds; D049308:Dioxygenases; D006841:Hydrocarbons, Aromatic; C010574:biphenyl