Metabolic pathway involved in 2-methyl-6-ethylaniline degradation by Sphingobium sp. strain MEA3-1 and cloning of the novel flavin-dependent monooxygenase system meaBA.

摘要: 2-Methyl-6-ethylaniline (MEA) is the main microbial degradation intermediate of chloroacetanilide herbicides acetochlor and metolachlor. Sphingobium sp. strain MEA3-1 can utilize MEA various alkyl-substituted aniline phenol compounds as sole carbon energy sources for growth. We isolated mutant MEA3-1Mut, which converts only to 2-methyl-6-ethyl-hydroquinone (MEHQ) 2-methyl-6-ethyl-benzoquinone (MEBQ). may be oxidized by P450 monooxygenase system 4-hydroxy-2-methyl-6-ethylaniline (4-OH-MEA), hydrolytically spontaneously deaminated MEBQ or MEHQ. The metabolic pathway was reconstituted based on substrate spectra identification metabolites in both wild-type strains. Plasmidome sequencing indicated that strains harbored 7 plasmids with sizes ranging from 6,108 bp 287,745 bp. Among plasmids, 6 were identical, pMEA02' MEA3-1Mut lost a 37,000-bp fragment compared pMEA02 MEA3-1. Two-dimensional electrophoresis (2-DE) protein mass fingerprinting (PMF) showed two-component flavin-dependent (TC-FDM) MeaBA, encoded gene pMEA02. MeaA shared 22% 25% amino acid sequence identity oxygenase components some TC-FDMs, whereas MeaB no reductase those TC-FDMs. Complementation meaBA heterologous expression Pseudomonas putida KT2440 resulted production an active MEHQ monooxygenase.