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Origins of the 2,4-dinitrotoluene pathway.

DIR@IMTECH: CSIR-Institute of Microbial Technology

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Title Origins of the 2,4-dinitrotoluene pathway.
 
Creator Johnson, G R
Jain, R K
Spain, Jim C
 
Subject QR Microbiology
 
Description 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.
 
Publisher ASM
 
Date 2002-08
 
Type Article
PeerReviewed
 
Format application/pdf
 
Identifier http://crdd.osdd.net/open/892/1/jain2002.pdf
Johnson, G R and Jain, R K and Spain, Jim C (2002) Origins of the 2,4-dinitrotoluene pathway. Journal of bacteriology, 184 (15). pp. 4219-32. ISSN 0021-9193
 
Relation http://jb.asm.org/content/184/15/4219.long
http://crdd.osdd.net/open/892/