title: Assimilation of aromatic compounds by Comamonas testosteroni: characterization and spreadability of protocatechuate 4,5-cleavage pathway in bacteria.
abstract: Comamonas testosteroni strain CNB-1 was isolated from activated sludge and has been investigated for its ability to degrade 4-chloronitrobenzene. Results from this study showed that strain CNB-1 grew on phenol, gentisate, vanillate, 3-hydroxybenzoate (3HB), and 4-hydroxybenzoate (4HB) as carbon and energy sources. Proteomic data and enzyme activity assays suggested that vanillate, 3HB, and 4HB were degraded in strain CNB-1 via protocatechuate (PCA) 4,5-cleavage pathway. The genetics and biochemistry of the PCA 4,5-cleavage pathway were investigated. Results showed that the 4-oxalomesaconate (OMA) hydratase from C. testosteroni takes only enol-OMA as substrate. A previously functionally unknown gene pmdU encodes an OMA tautomerase and catalyzes conversion of OMAketo into OMAenol. The 4-carboxy-4-hydroxy-2-oxoadipate (CHA) aldolase is encoded by pmdF and catalyzes the last step of the PCA 4,5-cleavage pathway. We explored the 1,183 microbial genomes at GenBank for potential PCA 4,5-cleavage pathways, and 33 putative pmd clusters were found. Results suggest that PCA 4,5-cleavage pathways are mainly distributed in α- and β-Proteobacteria.
authors.affiliation: State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, People's Republic of China.
authors.forename: Bin
authors.initials: B
authors.lastname: Ni
authors.forename: Yun
authors.initials: Y
authors.lastname: Zhang
authors.forename: Dong-Wei
authors.initials: DW
authors.lastname: Chen
authors.forename: Bao-Jun
authors.initials: BJ
authors.lastname: Wang
authors.forename: Shuang-Jiang
authors.initials: SJ
authors.lastname: Liu
mesh_terms: D001711:Biotransformation; D020604:Comamonas testosteroni / Q000235:genetics / Q000378:metabolism*; D019295:Computational Biology; D016680:Genome, Bacterial; D006841:Hydrocarbons, Aromatic / Q000378:metabolism*; D062385:Hydroxybenzoates / Q000378:metabolism*; D053858:Metabolic Networks and Pathways / Q000235:genetics*
chemical_list: D006841:Hydrocarbons, Aromatic; D062385:Hydroxybenzoates; C009091:protocatechuic acid