title: Proteogenomic evidence for β-oxidation of plant-derived 3-phenylpropanoids in "Aromatoleum aromaticum" EbN1.
abstract: The betaproteobacterium "Aromatoleum aromaticum" EbN1 utilizes eight different plant-derived nonhydroxylated (e.g. cinnamate) and hydroxylated (e.g. p-coumarate) 3-phenylpropanoids with nitrate as electron acceptor. Differential protein profiling (2D-DIGE) revealed abundance increases of five proteins (EbA5316 to EbA5320) during anaerobic growth with cinnamate, hydrocinnamate, p-coumarate, and 3-(4-hydroxyphenyl)propanoate, compared to anaerobic benzoate-adapted cells serving as reference state. The predicted functions of four of these proteins (EbA5317, fatty acid-coenzyme A (CoA) ligase; EbA5318, enoyl-CoA hydratase/isomerase; EbA5319, β-ketothiolase; and EbA5320, 3-hydroxyacyl-CoA dehydrogenase) suggest β-oxidation of the above 3-phenylpropanoids to benzoyl-CoA and p-hydroxybenzoyl-CoA, respectively. The fifth protein (EbA5316, ABC-type periplasmic solute-binding protein) could be involved in 3-phenylpropanoid uptake. The detection of 3-hydroxy-3-phenylpropanoate during anaerobic growth with cinnamate and hydrocinnamate or 3-hydroxy-3-(4-hydroxyphenyl)propanoate during anaerobic growth with p-coumarate and 3-(4-hydroxyphenyl)propanoate supports the proteome-predicted β-oxidation pathway. Based on the specific formation of EbA5316-20 also during anaerobic growth with further 3-phenylpropanoid growth substrates including cinnamyl alcohol, m-coumarate, 3-(3,4-dihydroxyphenyl)propanoate and 3,4-dihydroxycinnamate (caffeate), a common β-oxidation route is proposed for 3-phenylpropanoid degradation in strain EbN1. The low amount of metabolites attributable to cometabolic transformation of nongrowth supporting 3-phenylpropanoids (e.g. o-coumarate, ferulate) may be indicative for a high substrate specificity of the involved enzymes.
authors.affiliation: Carl-von-Ossietzky University, Oldenburg, Germany; Max Planck Institute for Marine Microbiology, Carl-von-Ossietzky Strasse 9-11, Bremen, Germany.
authors.forename: Kathleen
authors.initials: K
authors.lastname: Trautwein
authors.forename: Heinz
authors.initials: H
authors.lastname: Wilkes
authors.forename: Ralf
authors.initials: R
authors.lastname: Rabus
mesh_terms: D000214:Acyl Coenzyme A / Q000378:metabolism; D000693:Anaerobiosis / Q000502:physiology; D001426:Bacterial Proteins / Q000032:analysis / Q000378:metabolism*; D002934:Cinnamates / Q000378:metabolism*; D003373:Coumaric Acids / Q000378:metabolism; D015180:Electrophoresis, Gel, Two-Dimensional; D062385:Hydroxybenzoates / Q000378:metabolism; D053858:Metabolic Networks and Pathways; D010084:Oxidation-Reduction; D010666:Phenylpropionates / Q000378:metabolism*; D020005:Propanols / Q000378:metabolism; D011422:Propionates; D020543:Proteome / Q000032:analysis / Q000378:metabolism*; D040901:Proteomics; D043362:Rhodocyclaceae / Q000378:metabolism*
chemical_list: D000214:Acyl Coenzyme A; D001426:Bacterial Proteins; D002934:Cinnamates; D003373:Coumaric Acids; D062385:Hydroxybenzoates; D010666:Phenylpropionates; D020005:Propanols; D011422:Propionates; D020543:Proteome; C031579:beta-hydroxyphenylpropionic acid; C009091:protocatechuic acid; C037817:benzoyl-coenzyme A; C495469:p-coumaric acid; C020722:cinnamyl alcohol