AEM
Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Pflugmacher, U.
Right arrow Articles by Gottschalk, G.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Pflugmacher, U.
Right arrow Articles by Gottschalk, G.
Agricola
Right arrow Articles by Pflugmacher, U.
Right arrow Articles by Gottschalk, G.

 Previous Article  |  Next Article 

Appl. Environ. Microbiol., 11 1996, 3967-3977, Vol 62, No. 11
Copyright © 1996, American Society for Microbiology

Cloning, sequencing, and expression of isopropylbenzene degradation genes from Pseudomonas sp. strain JR1: identification of isopropylbenzene dioxygenase that mediates trichloroethene oxidation

U Pflugmacher, B Averhoff and G Gottschalk
Institut fur Mikrobiologie, Georg-August-Universitat Gottingen, Germany.

Pseudomonas sp. strain JR1, recently isolated with isopropylbenzene (IPB) as the inducer substrate for trichloroethene (TCE) oxidation (B. Dabrock, J. Riedel, J. Bertram, and G. Gottschalk, Arch. Microbiol 158:9-13, 1992), is able to degrade IPB via the meta-cleavage pathway. The genes encoding the first three enzymes in the catabolism of isopropylbenzene were isolated from a genomic library with the broad- host-range cosmid vector pWE15. A 7.6-kb fragment from a 37.7-kb primary cosmid clone was subcloned and sequenced. It contained seven complete open reading frames, designated ipbA1A2orf3A3A4BC. ipbA codes for the three subunits of a multicomponent IPB dioxygenase, ipbB codes for 2,3-dihydro-2,3-dihydroxy-IPB dehydrogenase, and ipbC codes for 3- isopropylcatechol 2,3-dioxygenase. The deduced amino acid sequences of ipbA1A2A3A4BC exhibited the highest homologies with the corresponding proteins of biphenyl-degradative pathways in gram-negative and gram- positive bacteria. The gene products of the ipb genes were identified by an in vitro transcription-translation system on the basis of their expected molecular masses. IPB dioxygenase and 3-isopropylcatechol 2,3- dioxygenase expressed in E. coli oxidized a wide range of alkyl aromatic compounds. Incubation of E. coli cells carrying ipbA1A2A3A4 with IPB and 10O2 yielded reaction products containing both atoms of molecular oxygen, which is in accordance with a dioxygenation reaction. E. coli recombinants harboring and expressing the IPB dioxygenase exhibited the ability to degrade TCE. The ipbA1A2A3A4-carrying E. coli strain required neither IPB nor isopropyl-beta-D-thiogalactopyranoside for induction; the rate of TCE degradation was comparable to that by fully induced Pseudomonas strain JR1.


This article has been cited by other articles:



Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
J. Bacteriol. Microbiol. Mol. Biol. Rev. Eukaryot. Cell All ASM Journals

Copyright © 1996 by the American Society for Microbiology. All rights reserved.