JB
Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow An erratum has been published
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 Johnson, G. R.
Right arrow Articles by Spain, J. C.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Johnson, G. R.
Right arrow Articles by Spain, J. C.
Journal of Bacteriology, August 2002, p. 4219-4232, Vol. 184, No. 15
0021-9193/02/$04.00+0     DOI: 10.1128/JB.184.15.4219-4232.2002
Copyright © 2002, American Society for Microbiology. All Rights Reserved.

Origins of the 2,4-Dinitrotoluene Pathway

Glenn R. Johnson, Rakesh K. Jain,,{dagger} and Jim C. Spain*

Air Force Research Laboratory, U.S. Air Force, Tyndall Air Force Base, Florida 32403

Received 11 February 2002/ Accepted 6 May 2002

The degradation of synthetic compounds requires bacteria to recruit and adapt enzymes from pathways for naturally occurring compounds. Previous work defined the steps in 2,4-dinitrotoluene (2,4-DNT) metabolism through the ring fission reaction. The results presented here characterize subsequent steps in the pathway that yield the central metabolic intermediates pyruvate and propionyl coenzyme A (CoA). The genes encoding the degradative pathway were identified within a 27-kb region of DNA cloned from Burkholderia cepacia R34, a strain that grows using 2,4-DNT as a sole carbon, energy, and nitrogen source. Genes for the lower pathway in 2,4-DNT degradation were found downstream from dntD, the gene encoding the extradiol ring fission enzyme of the pathway. The region includes genes encoding a CoA-dependent methylmalonate semialdehyde dehydrogenase (dntE), a putative NADH-dependent dehydrogenase (ORF13), and a bifunctional isomerase/hydrolase (dntG). Results from analysis of the gene sequence, reverse transcriptase PCR, and enzyme assays indicated that dntD dntE ORF13 dntG composes an operon that encodes the lower pathway. Additional genes that were uncovered encode the 2,4-DNT dioxygenase (dntAaAbAcAd), methylnitrocatechol monooxygenase (dntB), a putative LysR-type transcriptional (ORF12) regulator, an intradiol ring cleavage enzyme (ORF3), a maleylacetate reductase (ORF10), a complete ABC transport complex (ORF5 to ORF8), a putative methyl-accepting chemoreceptor protein (ORF11), and remnants from two transposable elements. Some of the additional gene products might play as-yet-undefined roles in 2,4-DNT degradation; others appear to remain from recruitment of the neighboring genes. The presence of the transposon remnants and vestigial genes suggests that the pathway for 2,4-DNT degradation evolved relatively recently because the extraneous elements have not been eliminated from the region.


* Corresponding author. Mailing address: Air Force Research Laboratory/MLQ, 139 Barnes Dr., Tyndall Air Force Base, FL 32403. Phone: (850) 283-6058. Fax: (850) 283 6090. E-mail: jim.spain{at}tyndall.af.mil.

{dagger} Present address: Institute of Microbial Technology, Sector 39-A, Chandigarh 160036, India.


Journal of Bacteriology, August 2002, p. 4219-4232, Vol. 184, No. 15
0021-9193/02/$04.00+0     DOI: 10.1128/JB.184.15.4219-4232.2002
Copyright © 2002, American Society for Microbiology. All Rights Reserved.




This article has been cited by other articles:




Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
Appl. Environ. Microbiol. Infect. Immun. Eukaryot. Cell
Mol. Cell. Biol. J. Virol. Microbiol. Mol. Biol. Rev.
ALL ASM JOURNALS

Copyright © 2002 by the American Society for Microbiology. All rights reserved.