Multiplicity of 2,3-Dihydroxybiphenyl Dioxygenase Genes in the Gram-positive Polychlorinated Biphenyl Degrading BacteriumRhodococcus rhodochrousK37

2004 ◽  
Vol 68 (4) ◽  
pp. 787-795 ◽  
Author(s):  
Katsuhiko TAGUCHI ◽  
Masaki MOTOYAMA ◽  
Toshiaki KUDO
Keyword(s):  
Polychlorinated Biphenyl ◽  
Gram Positive ◽  
Dihydroxybiphenyl Dioxygenase ◽  
Dioxygenase Genes

Expression inEscherichia coliof Biphenyl 2,3-Dioxygenase Genes from a Gram-Positive Polychlorinated Biphenyl Degrader,Rhodococcus jostiiRHA1

2011 ◽  
Vol 75 (1) ◽  
pp. 26-33
Author(s):  
Tsuneo OHMORI ◽  
Hirokazu MORITA ◽  
Megumi TANAKA ◽  
Masanori TOMOI ◽  
Keisuke MIYAUCHI ◽  
...  
Keyword(s):  
Polychlorinated Biphenyl ◽  
Gram Positive ◽  
Dioxygenase Genes

scholarly journals Evolutionarily Divergent Extradiol Dioxygenases Possess Higher Specificities for Polychlorinated Biphenyl Metabolites

2005 ◽  
Vol 187 (2) ◽  
pp. 415-421 ◽  
Author(s):  
Pascal D. Fortin ◽  
Andy T.-F. Lo ◽  
María-Amparo Haro ◽  
Stefan R. Kaschabek ◽  
Walter Reineke ◽  
...  
Keyword(s):  
Polychlorinated Biphenyl ◽  
Substrate Binding ◽  
Structural Data ◽  
Binding Pocket ◽  
Distal Portion ◽  
The Other ◽  
Substrate Binding Pocket ◽  
Dihydroxybiphenyl Dioxygenase ◽  
Extradiol Dioxygenases ◽  
Better Than

ABSTRACT The reactivities of four evolutionarily divergent extradiol dioxygenases towards mono-, di-, and trichlorinated (triCl) 2,3-dihydroxybiphenyls (DHBs) were investigated: 2,3-dihydroxybiphenyl dioxygenase (EC 1.13.11.39) from Burkholderia sp. strain LB400 (DHBDLB400), DHBDP6-I and DHBDP6-III from Rhodococcus globerulus P6, and 2,2′,3-trihydroxybiphenyl dioxygenase from Sphingomonas sp. strain RW1 (THBDRW1). The specificity of each isozyme for particular DHBs differed by up to 3 orders of magnitude. Interestingly, the K m app values of each isozyme for the tested polychlorinated DHBs were invariably lower than those of monochlorinated DHBs. Moreover, each enzyme cleaved at least one of the tested chlorinated (Cl) DHBs better than it cleaved DHB (e.g., apparent specificity constants for 3′,5′-dichlorinated [diCl] DHB were 2 to 13.4 times higher than for DHB). These results are consistent with structural data and modeling studies which indicate that the substrate-binding pocket of the DHBDs is hydrophobic and can accommodate the Cl DHBs, particularly in the distal portion of the pocket. Although the activity of DHBDP6-III was generally lower than that of the other three enzymes, six of eight tested Cl DHBs were better substrates for DHBDP6-III than was DHB. Indeed, DHBDP6-III had the highest apparent specificity for 4,3′,5′-triCl DHB and cleaved this compound better than two of the other enzymes. Of the four enzymes, THBDRW1 had the highest specificity for 2′-Cl DHB and was at least five times more resistant to inactivation by 2′-Cl DHB, consistent with the similarity between the latter and 2,2′,3-trihydroxybiphenyl. Nonetheless, THBDRW1 had the lowest specificity for 2′,6′-diCl DHB and, like the other enzymes, was unable to cleave this critical PCB metabolite (k cat app < 0.001 s−1).

Characterization of a Defined 2,3,5,6-Tetrachlorobiphenyl-ortho-Dechlorinating Microbial Community by Comparative Sequence Analysis of Genes Coding for 16S rRNA

1998 ◽  
Vol 64 (9) ◽  
pp. 3359-3367 ◽  
Author(s):  
Tracey R. Pulliam Holoman ◽  
Margaret A. Elberson ◽  
Leah A. Cutter ◽  
Harold D. May ◽  
Kevin R. Sowers
Keyword(s):  
Fatty Acids ◽  
16S Rdna ◽  
Polychlorinated Biphenyl ◽  
Sequence Similarity ◽  
Bacterial Species ◽  
Community Diversity ◽  
Molecular Monitoring ◽  
Gram Positive ◽  
Enrichment Cultures ◽  
Sequence Similarities

ABSTRACT Defined microbial communities were developed by combining selective enrichment with molecular monitoring of total community genes coding for 16S rRNAs (16S rDNAs) to identify potential polychlorinated biphenyl (PCB)-dechlorinating anaerobes that orthodechlorinate 2,3,5,6-tetrachlorobiphenyl. In enrichment cultures that contained a defined estuarine medium, three fatty acids, and sterile sediment, a Clostridium sp. was predominant in the absence of added PCB, but undescribed species in the δ subgroup of the class Proteobacteria, the low-G+C gram-positive subgroup, the Thermotogales subgroup, and a single species with sequence similarity to the deeply branching speciesDehalococcoides ethenogenes were more predominant during active dechlorination of the PCB. Species with high sequence similarities to Methanomicrobiales andMethanosarcinales archaeal subgroups were predominant in both dechlorinating and nondechlorinating enrichment cultures. Deletion of sediment from PCB-dechlorinating enrichment cultures reduced the rate of dechlorination and the diversity of the community. Substitution of sodium acetate for the mixture of three fatty acids increased the rate of dechlorination, further reduced the community diversity, and caused a shift in the predominant species that included restriction fragment length polymorphism patterns not previously detected. Although PCB-dechlorinating cultures were methanogenic, inhibition of methanogenesis and elimination of the archaeal community by addition of bromoethanesulfonic acid only slightly inhibited dechlorination, indicating that the archaea were not required for ortho dechlorination of the congener. Deletion of Clostridium spp. from the community profile by addition of vancomycin only slightly reduced dechlorination. However, addition of sodium molybdate, an inhibitor of sulfate reduction, inhibited dechlorination and deleted selected species from the community profiles of the class Bacteria. With the exception of one 16S rDNA sequence that had the highest sequence similarity to the obligate perchloroethylene-dechlorinating Dehalococcoides, the 16S rDNA sequences associated with PCB ortho dechlorination had high sequence similarities to the δ, low-G+C gram-positive, andThermotogales subgroups, which all include sulfur-, sulfate-, and/or iron(III)-respiring bacterial species.

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