Monooxygenase, a Novel Beta-Cypermethrin Degrading Enzyme from Streptomyces sp

• Published in: PloS one Vol. 8; no. 9; p. e75450
• Main Authors: Chen, Shaohua, Lin, Qingsheng, Xiao, Ying, Deng, Yinyue, Chang, Changqing, Zhong, Guohua, Hu, Meiying, Zhang, Lian-Hui
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 30.09.2013; Public Library of Science (PLoS)
• Subjects: Aluminum; Bacillus cereus; Base Sequence; Biodegradation; Biology; Cloning; Contamination; Copper; Cypermethrin; Degradation; Detoxification; Environmental effects; Environmental Pollution - prevention & control; Environmental protection; Enzymatic activity; Enzyme activity; Enzymes; Homogeneity; Hydrogen-Ion Concentration; Hydrolase; Hydroxylation; Insecticides; Insecticides - metabolism; Ionization; Iron; Mass spectrometry; Mass spectroscopy; Metals, Heavy - pharmacology; Methods; Microorganisms; Mixed Function Oxygenases - chemistry; Mixed Function Oxygenases - genetics; Mixed Function Oxygenases - isolation & purification; Mixed Function Oxygenases - metabolism; Molecular Sequence Data; Molecular structure; Molecular Weight; Monooxygenase; Natural resources; Pesticide pollution; Pesticides; pH effects; Proteins; Public concern; Pyrethrins - metabolism; Pyrethroids; Sequence Analysis, DNA; Soil contamination; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Sphingobium; Streptomyces; Streptomyces - enzymology; Substrates; Temperature; Terminal protein; Toxicity; China; Singapore
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0075450

The widely used insecticide beta-cypermethrin has become a public concern because of its environmental contamination and toxic effects on mammals. In this study, a novel beta-cypermethrin degrading enzyme designated as CMO was purified to apparent homogeneity from a Streptomyces sp. isolate capable of utilizing beta-cypermethrin as a growth substrate. The native enzyme showed a monomeric structure with a molecular mass of 41 kDa and pI of 5.4. The enzyme exhibited the maximal activity at pH 7.5 and 30°C. It was fairly stable in the pH range from 6.5-8.5 and at temperatures below 10°C. The enzyme activity was significantly stimulated by Fe(2+), but strongly inhibited by Ag(+), Al(3+), and Cu(2+). The enzyme catalyzed the degradation of beta-cypermethrin to form five products via hydroxylation and diaryl cleavage. A novel beta-cypermethrin detoxification pathway was proposed based on analysis of these products. The purified enzyme was identified as a monooxygenase by matrix-assisted laser desorption/ionization time-of-flight/time-of-flight mass spectrometry analysis (MALDI-TOF-MS) and N-terminal protein sequencing. Given that all the characterized pyrethroid-degrading enzymes are the members of hydrolase family, CMO represents the first pyrethroid-degrading monooxygenase identified from environmental microorganisms. Taken together, our findings depict a novel pyrethroid degradation mechanism and indicate that the purified enzyme may be a promising candidate for detoxification of beta-cypermethrin and environmental protection.