Cloning and Characterization of a 4-Nitrophenol Hydroxylase Gene Cluster from Rhodococcus sp. PN1.

Abstract

A 4-nitrophenol (4-NP)-degrading bacterium was isolated from activated sludge and identified as a Rhodococcus sp. This bacterium, designated as strain PN1, could utilize 4-NP as a sole carbon, nitrogen and energy source. Degradation tests of 4-NP using cell suspensions of strain PN1 revealed that the degradation was induced by 4-NP and that 4-nitrocatechol (4-NC) was one of the metabolites. A gene library was constructed from the total DNA of strain PN1 and introduced into Rhodococcus rhodochrous ATCC 12674. Two recombinant strains showed 4-NP hydroxylase activity, and a 9.1-kb DNA fragment encoding the activity was isolated from one of the strains. In addition, a 2.4-kb smaller fragment expressing the activity was subcloned from the 9.1-kb fragment and sequenced. The sequence analysis showed that the fragment encodes a two-component 4-NP hydroxylase, the predicted amino acid sequence of which exhibits significant similarity to those of phenol hydroxylases and 4-hydroxyphenylacetate 3-hydroxylases belonging to the two-component flavin diffusible monooxygenase (TC-FDM) family proposed by Galán et al. (J. Bacteriol., 182, 627-636, 2000).

Expression, purification, crystallization and preliminary X-ray analysis ofpara-nitrophenol 4-monooxygenase fromPseudomonas putidaDLL-E4

“…It is used in the synthesis of medicines, dyes, explosives, leather colouring, wood preservatives and rubber chemicals (Uberio & Bhattacharya, 1997). Microbial degradation of PNP has been studied for more than 20 years, but the genes involved in the degradation pathways have only recently been cloned (Wataru et al, 2004;Takeo et al, 2003, Perry & Zylstra, 2007. Degradation of PNP by microorganisms commonly takes place through two different pathways in pure cultures: via para-benzoquinone (HQ) or 4-nitrocatechol (4-NC) under aerobic conditions (Wataru et al, 2004).…”

“…(Spain et al, 1991); in Gram-positive strains, PNP is first converted to 1,2,4-benzenetriol by monooxygenases as in Rhodococcus sp. PN1 (Takeo et al, 2003), R. opacus SAO101 (Wataru et al, 2004) and Arthrobacter sp. JS443 (Perry & Zylstra, 2007).…”

Mineralization ofp-nitrophenol by a new isolateArthrobactersp. Y1

“…[1] The use of such materials has resulted in the release of nitrophenols into the environment. [2] Among them, p-nitrophenol is one of the main hydrolysis products of parathion and methyl parathion and it shows enhanced toxicity towards soil microflora. [3] It is also generated during formulation, distribution, and field application of pesticides or photodegradation of pesticides that contain the nitrophenol moiety.…”

“…[13] In addition, the PNP-degrading gene clusters had been reported using the method of genome library construction. [2,14] In this study, enrichments were set up to isolate PNPdegrading bacteria which could tolerate high concentrations of PNP. The nitrite released could be removed without adding additional processes.…”

Catabolism of alkylphenols inRhodococcusvia ameta-cleavage pathway associated with genomic islands

“…304 BUBNP1 (WP_059382681.1)(Sengupta et al, 2019) and NphA1 from Rhodococcus sp. PN1 305 (Q8RQQ0)(Takeo et al, 2003). Despite 100% sequence identity with NphA1BUBNP1, PheA EP4 306…”