title: SulE, a sulfonylurea herbicide de-esterification esterase from Hansschlegelia zhihuaiae S113.
abstract: De-esterification is an important degradation or detoxification mechanism of sulfonylurea herbicide in microbes and plants. However, the biochemical and molecular mechanisms of sulfonylurea herbicide de-esterification are still unknown. In this study, a novel esterase gene, sulE, responsible for sulfonylurea herbicide de-esterification, was cloned from Hansschlegelia zhihuaiae S113. The gene contained an open reading frame of 1,194 bp, and a putative signal peptide at the N terminal was identified with a predicted cleavage site between Ala37 and Glu38, resulting in a 361-residue mature protein. SulE minus the signal peptide was synthesized in Escherichia coli BL21 and purified to homogeneity. SulE catalyzed the de-esterification of a variety of sulfonylurea herbicides that gave rise to the corresponding herbicidally inactive parent acid and exhibited the highest catalytic efficiency toward thifensulfuron-methyl. SulE was a dimer without the requirement of a cofactor. The activity of the enzyme was completely inhibited by Ag(+), Cd(2+), Zn(2+), methamidophos, and sodium dodecyl sulfate. A sulE-disrupted mutant strain, ΔsulE, was constructed by insertion mutation. ΔsulE lost the de-esterification ability and was more sensitive to the herbicides than the wild type of strain S113, suggesting that sulE played a vital role in the sulfonylurea herbicide resistance of the strain. The transfer of sulE into Saccharomyces cerevisiae BY4741 conferred on it the ability to de-esterify sulfonylurea herbicides and increased its resistance to the herbicides. This study has provided an excellent candidate for the mechanistic study of sulfonylurea herbicide metabolism and detoxification through de-esterification, construction of sulfonylurea herbicide-resistant transgenic crops, and bioremediation of sulfonylurea herbicide-contaminated environments.
authors.affiliation: Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, China.
authors.forename: Bao-Jian
authors.initials: BJ
authors.lastname: Hang
authors.forename: Qing
authors.initials: Q
authors.lastname: Hong
authors.forename: Xiang-Ting
authors.initials: XT
authors.lastname: Xie
authors.forename: Xing
authors.initials: X
authors.lastname: Huang
authors.forename: Cheng-Hong
authors.initials: CH
authors.lastname: Wang
authors.forename: Jian
authors.initials: J
authors.lastname: He
authors.forename: Shun-Peng
authors.initials: SP
authors.lastname: Li
mesh_terms: D002413:Cations, Divalent / Q000378:metabolism; D003001:Cloning, Molecular; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004791:Enzyme Inhibitors / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D004950:Esterases / Q000235:genetics* / Q000378:metabolism*; D004951:Esterification; D017353:Gene Deletion; D006540:Herbicides / Q000378:metabolism*; D008670:Metals / Q000378:metabolism; D042083:Methylocystaceae / Q000201:enzymology* / Q000235:genetics*; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D009946:Organothiophosphorus Compounds / Q000378:metabolism; D055503:Protein Multimerization; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D017422:Sequence Analysis, DNA; D012967:Sodium Dodecyl Sulfate / Q000378:metabolism; D013379:Substrate Specificity; D013453:Sulfonylurea Compounds / Q000378:metabolism*
chemical_list: D002413:Cations, Divalent; D004269:DNA, Bacterial; D004791:Enzyme Inhibitors; D006540:Herbicides; D008670:Metals; D009946:Organothiophosphorus Compounds; D013453:Sulfonylurea Compounds; D012967:Sodium Dodecyl Sulfate; C014655:methamidophos; D004950:Esterases