Comamonas testosteroni BR6020 possesses a single genetic locus for extradiol cleavage of protocatechuate.
A key intermediate for biodegradation of various distinct aromatic growth substrates in Comamonas testosteroni is protocatechuate (Pca), which is metabolized by the 4,5-extradiol (meta) ring fission pathway. A locus harbouring genes from C. testosteroni BR6020 was cloned, dubbed pmd, which encodes the enzymes that degrade Pca. The identity of pmdAB, encoding respectively the alpha- and beta-subunit of the Pca ring-cleavage enzyme, was confirmed by N-terminal sequencing and molecular mass determination of both subunits from the separated enzyme. Disruption of pmdA resulted in a strain unable to grow on Pca and a variety of aromatic substrates funnelled through this compound (m- and p-hydroxybenzoate, p-sulfobenzoate, phthalate, isophthalate, terephthalate, vanillate, isovanillate and veratrate). Growth on benzoate and o-aminobenzoate (anthranilate) was not affected in this strain, indicating that these substrates are metabolized via a different lower pathway. Tentative functions for the products of other pmd genes were assigned based on sequence identity and/or similarity to proteins from other proteobacteria involved in uptake or metabolism of aromatic compounds. This study provides evidence for a single lower pathway in C. testosteroni for metabolism of Pca, which is generated by different upper pathways acting on a variety of aromatic substrates.
Providenti
Miguel A
MA
Faculty of Biology, The University, D-78457, Konstanz, Germany2.|Institute of Biology, College of Natural Sciences, Carleton University, Ottawa, Ontario, CanadaK1S 5B61.
Mampel
Jörg
J
Faculty of Biology, The University, D-78457, Konstanz, Germany2.
MacSween
Scott
S
Institute of Biology, College of Natural Sciences, Carleton University, Ottawa, Ontario, CanadaK1S 5B61.
Cook
Alasdair M
AM
Faculty of Biology, The University, D-78457, Konstanz, Germany2.
Wyndham
R Campbell
RC
Institute of Biology, College of Natural Sciences, Carleton University, Ottawa, Ontario, CanadaK1S 5B61.
D000595:Amino Acid Sequence; D001483:Base Sequence; D001673:Biodegradation, Environmental; D003001:Cloning, Molecular; D020604:Comamonas testosteroni / Q000201:enzymology* / Q000235:genetics*; D003470:Culture Media; D049308:Dioxygenases; D006841:Hydrocarbons, Aromatic / Q000378:metabolism; D062385:Hydroxybenzoates / Q000378:metabolism*; D008969:Molecular Sequence Data; D010105:Oxygenases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D017422:Sequence Analysis, DNA
D003470:Culture Media; D006841:Hydrocarbons, Aromatic; D062385:Hydroxybenzoates; C009091:protocatechuic acid; D010105:Oxygenases; D049308:Dioxygenases; C022476:protocatechuate 4,5-dioxygenase