The Two-Component Monooxygenase MeaXY Initiates the Downstream Pathway of Chloroacetanilide Herbicide Catabolism in Sphingomonads

• DOI: 10.1128/aem.03241-16
• Publication Date: 2017-01-24T02:45:44Z
• Authors: Minggen Cheng; Qiang Meng; Youjian Yang; Cuiwei Chu; Qing Chen; Yi Li; Dan Cheng; Qing Hong; Xin Yan; Jian He
• Keywords: Hydroxylation; Catabolism; Metabolic pathway

Due to the extensive use of chloroacetanilide herbicides over past 60 years, bacteria have evolved catabolic pathways mineralize these compounds. In upstream pathway, are transformed into two common metabolites 2-methyl-6-ethylaniline (MEA) and 2,6-diethylaniline (DEA) through N-dealkylation amide hydrolysis. The pathway downstream MEA is initiated by hydroxylation aromatic rings, followed its conversion a substrate for ring cleavage after several steps. Most key genes in been identified. However, involved initial step still unknown. As special aniline derivative, cannot be dioxygenases that characterized. Sphingobium baderi DE-13 can completely degrade it as sole carbon source growth. this work, an degradation-deficient mutant S. was isolated. catabolism were predicted comparative genomic analysis. results genetic complementation heterologous expression demonstrated products meaX meaY responsible degradation DE-13. MeaXY two-component flavoprotein monooxygenase system catalyzes DEA using NADH flavin mononucleotide (FMN) cofactors. Nuclear magnetic resonance (NMR) analysis confirmed hydroxylates at para-position. Transcription enhanced remarkably upon induction or Additionally, highly conserved among other MEA-degrading sphingomonads. This study fills gap our knowledge biochemical carries out mineralization sphingomonads.IMPORTANCE Much attention has paid environmental fate used years. Microbial considered important mechanism Bacterial investigated many recent studies. Pure cultures consortia able obtained. proposed, most initiation (from hydroxylated from DEA) not reported. present demonstrates flavin-dependent system, MeaXY, para-hydroxylation Therefore, work finds missing link expand understanding kind derivative.