Cytochrome P450 Initiates Degradation ofcis-Dichloroethene by Polaromonas sp. Strain JS666

Abstract

bPolaromonas sp. strain JS666 grows on cis-1,2-dichoroethene (cDCE) as the sole carbon and energy source under aerobic conditions, but the degradation mechanism and the enzymes involved are unknown. In this study, we established the complete pathway for cDCE degradation through heterologous gene expression, inhibition studies, enzyme assays, and analysis of intermediates. Several lines of evidence indicate that a cytochrome P450 monooxygenase catalyzes the initial step of cDCE degradation. Both the transient accumulation of dichloroacetaldehyde in cDCE-degrading cultures and dichloroacetaldehyde dehydrogenase activities in cell extracts of JS666 support a pathway for degradation of cDCE through dichloroacetaldehyde. The mechanism minimizes the formation of cDCE epoxide. The molecular phylogeny of the cytochrome P450 gene and the organization of neighboring genes suggest that the cDCE degradation pathway recently evolved in a progenitor capable of degrading 1,2-dichloroethane either by the recruitment of the cytochrome P450 monooxygenase gene from an alkane catabolic pathway or by selection for variants of the P450 in a preexisting 1,2-dichloroethane catabolic pathway. The results presented here add yet another role to the broad array of productive reactions catalyzed by cytochrome P450 enzymes.

The Enzymology of Organic Transformations: A Survey of Name Reactions in Biological Systems

“…[235] This reaction has been proposed to be a key step in the catabolism of nitrobenzene in a species of Pseudomonas pseudocaligenes which can utilize nitrobenzene as a sole carbon, nitrogen, and energy source (Figure 64b). [236] This is based on the observation that conversion of hydroxylaminobenzene to 2-aminophenol could be achieved using cell-free lysate of P. pseudocaligenes , suggesting a “Bamberger-like” rearrangement. Similar Bamberger-like rearrangements are thought to occur in the catabolism of chloronitrobenzene in bacterial strain LW1 of the family Comamonadaceae , [237] 4-nitrotoluene in Mycobacterium sp .…”

Enzyme activity and gene expression profiles of Xanthobacter autotrophicus GJ10 during aerobic biodegradation of 1,2-dichloroethane

“…strain DCA1 (Hage and Hartmans Hage and Hartmans 1999) have also been reported to degrade 1,2-DCA by an oxidative pathway similar to strain JS666 which is inconsistent with the pathway shown by GJ10. The GC-MS analysis shows the formation of dichloroacetaldehyde and one unidentified compound during cis-dichloroethene degradation by JS666 (Nishino et al 2013), whereas chloroacetaldehyde was detected during 1,2-DCA degradation by GJ10 in this study. Therefore, although the initial step for the degradation of 1,2-DCA and cis-dichloroethene in the different organisms involves different enzymes and pathways, chloroacetaldehyde seems to be the central metabolite produced during the degradation process (Stucki et al 1983;Hage and Hartmans 1999;Janssen et al 1994;Nishino et al 2013).…”

“…strain JS666, shows that cis-dichloroethene is also degraded via dichloroacetaldehyde but the first step is initiated by Cytochrome P450 (cDCA monooxygenase) (Nishino et al 2013). However, GJ10 degrades 1,2-DCA by the hydrolytic pathway while JS666 (Nishino et al 2013) degrades cis-dichloroethene by an oxidative pathway. Pseudomonas sp.…”

The Bacteria and the TirHaloMethanes in Drinking Water Distribution System in Jazan Region

“…Polaromonas sp. an aerobic bacterial species belonging to order Burkholderiales capable of growth on chlorine compound like cis-dichloroethene as a sole carbon and energy source was isolated by [54,55]. Gamma -Proteobacteria the most important class of bacteria in the bacterial isolates from south area was (≈26.7%) of the total bacterial isolates and 40.8% if we consider the south areas only "El-Ahad, El-Dagarer and Samta".…”