Structural highlights
Function
NPCA_RHOOP Involved in the degradation of para-nitrophenol (4-NP). Catalyzes both the initial hydroxylation of 4-NP to produce 4-nitrocatechol (4-NCA) and the subsequent oxidative release of the nitro group from 4-NCA to produce 2-hydroxy-1,4-benzoquinone. It can also use 4-nitroresorcinol as substrate with a rate of nitrite release similar to that observed with the two physiological substrates, 4-PN and 4-NCA.[1] [2]
Publication Abstract from PubMed
BACKGROUND: Bioremediation relying on highly efficient degrading bacteria constitutes a promising and sustainable avenue for controlling and reducing nitrophenol contamination in the environment. A thorough understanding of the bacterial degradation mechanism of nitrophenol is of paramount importance for supporting the development of efficient microbial remediation technology. RESULTS: In this study, a new bacterium, Rhodococcus sp. 21391, endowed with superior p-nitrophenol (PNP) degradation ability was obtained. Genomic and comparative proteomic analyses revealed that it utilizes the 1,2,4-benzenetriol (BT) pathway for PNP degradation. The catalytic properties of the two-component p-nitrophenol monooxygenase RsNcpAB from the strain were investigated in vitro. The enzyme exhibited a broad substrate selectivity, catalyzing the oxidation of various nitrophenols and halogenated phenols, with significant potential for further research and development. Additionally, the crystal structure of the oxidative component of p-nitrophenol monooxygenase, RsNcpA, was determined. Structural analysis and site-directed mutagenesis revealed that residues Arg100 and His293 in the active site play a crucial role in enzyme catalysis, and a catalytic mechanism model was subsequently proposed. CONCLUSIONS: This study reports a high-performance nitrophenol-degrading bacterium and enzyme, and reveals their mechanisms at the molecular level. These findings increase the understanding of the bacterial degradation of nitrophenol, thereby providing a crucial foundation for the development of efficient bioremediation technologies.
Biodegradation of p-nitrophenol by Rhodococcus sp. 21391 unveils a two-component p-nitrophenol monooxygenase with broad substrate specificity.,Yang J, Lin S, Li W, Wang X, Li R Microb Cell Fact. 2025 Apr 17;24(1):85. doi: 10.1186/s12934-025-02712-1. PMID:40247276[3]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Kitagawa W, Kimura N, Kamagata Y. A novel p-nitrophenol degradation gene cluster from a gram-positive bacterium, Rhodococcus opacus SAO101. J Bacteriol. 2004 Aug;186(15):4894-902. PMID:15262926 doi:10.1128/JB.186.15.4894-4902.2004
- ↑ Kadiyala V, Spain JC. A two-component monooxygenase catalyzes both the hydroxylation of p-nitrophenol and the oxidative release of nitrite from 4-nitrocatechol in Bacillus sphaericus JS905. Appl Environ Microbiol. 1998 Jul;64(7):2479-84. PMID:9647818 doi:10.1128/AEM.64.7.2479-2484.1998
- ↑ Yang J, Lin S, Li W, Wang X, Li R. Biodegradation of p-nitrophenol by Rhodococcus sp. 21391 unveils a two-component p-nitrophenol monooxygenase with broad substrate specificity. Microb Cell Fact. 2025 Apr 17;24(1):85. PMID:40247276 doi:10.1186/s12934-025-02712-1
