(Below N is a link to NCBI taxonomic web page and E link to ESTHER at designed phylum.) > cellular organisms: NE > Bacteria: NE > Proteobacteria: NE > Alphaproteobacteria: NE > Rhizobiales: NE > Methylocystaceae: NE > Hansschlegelia: NE > Hansschlegelia zhihuaiae: NE
LegendThis sequence has been compared to family alignement (MSA) red => minority aminoacid blue => majority aminoacid color intensity => conservation rate title => sequence position(MSA position)aminoacid rate Catalytic site Catalytic site in the MSA METDKKTGTSRRSFVKAAGTGAIGIATLPLSTATAFAETDNVELAQSKRK VVLAEQGSFYIGGRTVTGPGKFDPSKPVIPYSNEGATFYINQMYVNFQAP VRPRGLPLVFWHGGGLTGHIWESTPDGRPGFQTLFVQDRHTVYTIDQPGR GRGNIPTFNGPFGQLEEESIVNTVTGNSSKEGAWVRDRLGPAPGQFFENS QFPRGYEDNYFKEMGFSPSISSDEIVDAVVKLVTHIGPCVLVTHSASGVL GMRVATHAKNVRGIVAYEPATSIFPKGKVPEIPPLADKKSQIFPPFEIQE SYFKKLAKIPIQFVFGDNIPKNPKSAYWFLDWWRVTRYAHSLSLEAINKL GGQASLLDLPTAGLRGNTHFPFTDRNNVQVASLLSDFLGKHGLDQNES
References
Title: Directed Evolution of Sulfonylurea Esterase and Characterization of a Variant with Improved Activity Liu B, Peng Q, Sheng M, Hu S, Qian M, Fan B, He J Ref: Journal of Agricultural and Food Chemistry, 67:836, 2019 : PubMed
Esterase SulE detoxicates a variety of sulfonylurea herbicides through de-esterification. SulE exhibits high activity against thifensulfuron-methyl but low activity against other sulfonylureas. In this study, two variants, m2311 (P80R) and m0569 (P80R and G176A), with improved activity were screened from a mutation library constructed by error-prone PCR. Variant m2311 showed a higher activity against sulfonylureas in comparison variant m0569 and was further investigated. The kcat/ Km value of variant m2311 for metsulfuron-methyl, sulfometuron-methyl, chlorimuron-ethyl, tribenuron-methyl, and ethametsulfuron-methyl increased by 3.20-, 1.72-, 2.94-, 2.26- and 2.96-fold, respectively, in comparison with the wild type. Molecular modeling suggested that the activity improvement of variant m2311 is due to the substitution of Pro80 by arginine, leading to the formation of new hydrogen bonds between the enzyme and substrate. This study facilitates further elucidation of the structure and function of SulE and provides an improved gene resource for the detoxification of sulfonylurea residues and the genetic engineering of sulfonylurea-resistant crops.
Title: SulE, a sulfonylurea herbicide de-esterification esterase from Hansschlegelia zhihuaiae S113 Hang BJ, Hong Q, Xie XT, Huang X, Wang CH, He J, Li SP Ref: Applied Environmental Microbiology, 78:1962, 2012 : PubMed
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, DeltasulE, was constructed by insertion mutation. DeltasulE 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.
