Studies on the isopropylbenzene 2,3-dioxygenase and the 3-isopropylcatechol 2,3-dioxygenase genes encoded by the linear plasmid of Rhodococcus erythropolis BD2

• Published in: Microbiology (Society for General Microbiology) Vol. 142; no. 11; pp. 3241 - 3251
• Main Authors: Kesseler, Maria, Dabbs, Eric R, Averhoff, Beate, Gottschalk, Gerhard
• Format: Journal Article
• Language: English
• Published: Reading Soc General Microbiol 01.11.1996; Society for General Microbiology
• Subjects: Amino Acid Sequence; Bacteriology; Base Sequence; Biological and medical sciences; Biology of microorganisms of confirmed or potential industrial interest; Biotechnology; Catechols - pharmacology; Chromosome Mapping; Cloning, Molecular; Dioxygenases; DNA, Bacterial - genetics; Enzyme Inhibitors - pharmacology; Escherichia coli - genetics; Fundamental and applied biological sciences. Psychology; Genes, Bacterial; Genetics; Microbiology; Mission oriented research; Molecular Sequence Data; Multigene Family; Oxygenases - antagonists & inhibitors; Oxygenases - genetics; Plasmids - genetics; Rhodococcus - enzymology; Rhodococcus - genetics; Trichloroethylene - metabolism; Biodegradation; Nucleotide sequence; Enzyme; Trichloroethylene; Gene organization; Metabolism; Plasmid; Pollutant; Enzymatic activity; DNA; Bacteria; Actinomycetes; Oxidation; Aminoacid sequence
• ISSN: 1350-0872; 1465-2080
• DOI: 10.1099/13500872-142-11-3241

1 Institut für Mikrobiologie der Georg-August-Universität, Grisebachstraße 8, D-37077 Göttingen, Germany 2 University of the Witwatersrand, Johannesburg, South Africa ABSTRACT The enzymes responsible for the degradation of isopropylbenzene (IPB) and co-oxidation of trichloroethene (TCE) by Rhodococcus erythropolis BD2 are encoded by the linear plasmid pBD2. Fragments containing IPB catabolic genes were cloned from pBD2 and the nucleotide sequence was determined. By means of database searches and expression of the cloned genes in recombinant strains, we identified five clustered genes, ipbA1A2A3A4C, which encode the three components of the IPB 2,3-dioxygenase system, reductase IPB ( ipbA4 ), ferredoxin IPB ( ipbA3 ) and the two subunits of the terminal dioxygenase ( ipbA1A2 ), as well as the 3-isopropylcatechol (IPC) 2,3-dioxygenase ( ipbC ). The protein sequences deduced from the ipbA1A2A3A4C gene cluster exhibited significant homology with the corresponding proteins of analogous degradative pathways in Gram-negative and Gram-positive bacteria, but the gene order differed from most of them. IPB 2,3-dioxygenase and 3-IPC 2,3-dioxygenase could both be expressed in Escherichia coli, but the IPB 2,3-dioxygenase activities were too low to be detected by polarographic and TCE degradative means. However, inhibitor studies with the R. erythropolis BD2 wild-type are in accordance with the involvement of the IPB 2,3-dioxygenase in TCE oxidation. 3 Author for correspondence: Beate Averhoff. Tel: +49 551 394041. Fax: +49 551 393793. Keywords: Rhodococcus erythropolis , isopropylbenzene 2,3-dioxygenase, 3-isopropyl-catechol 2,3-dioxygenase, trichloroethene co-oxidation