- Characterization of a novel thermophilic pyrethroid-hydrolyzing carboxylesterase from Sulfolobus tokodaii into a new family
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A novel gene ST2026 encoding a putative carboxylesterase from the thermophilic crenarchaeota Sulfolobus tokodaii (named EstSt7) was cloned and functionally overexpressed in Escherichia coli. The recombinant enzyme was purified to homogeneity after heat treatment, Ni-NTA affinity and Superdex-200 gel filtration chromatography. EstSt7 showed maximum activity at 80 C over 30 min and had a half-life of 180 min at 90 C. Its enzymatic activity was stable in the pH range of 8.0-10.0 with an optimum at 9.0. The enzyme exhibited significant esterase activity toward various p-nitrophenyl esters and the most preferable substrate was p-nitrophenyl butyrate (kcat/Km of 246.3 s-1 mM-1). In addition, EstSt7 showed high activity and stability against organic solvents (20% and 50% v/v) and detergents (1% and 5% v/v). Furthermore, EstSt7 could efficiently hydrolyze a wide range of synthetic pyrethroids including fenpropathrin, permethrin, cypermethrin, cyhalothrin, deltamethrin and bifenthrin, which makes it a potential candidate for the detoxification of pyrethroids for the purpose of biodegradation. Sequence alignment, phylogenetic analysis and comparison of the conserved motif reveal that this novel carboxylesterase EstSt7 should be grouped into a new bacterial lipase and esterase family.
- Wei, Tao,Feng, Shengxue,Shen, Yulong,He, Peixin,Ma, Geli,Yu, Xuan,Zhang, Fei,Mao, Duobin
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p. 225 - 232
(2013/10/21)
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- PRACTICAL AND STEREOCONTROLLED SYNTHESES OF BOTH (1R*,3S*)- AND (1R*,3R*)-3-(2-CHLORO-3,3,3-TRIFLUORO-1-PROPENYL)-2,2-DIMETHYLCYCLOPROPANECARBOXYLATES
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The title compounds of (1R*,3S*) configuration were prepared from 3-formyl-2,2-dimethylcyclopropanecarboxylate by addition of CF3CCl2ZnCl, acetylation, and reductive β-elimination with zinc, whereas the (1R*,3R*) isomer was derived from Me2C=CHCH(OH)CCl2CF3 by diazoacetylation, Cu(II) catalyzed intramolecular cyclization, and the zinc reduction.
- Fujita, Makoto,Hiyama, Tamejiro,Kondo, Kiyosi
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p. 2139 - 2142
(2007/10/02)
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- Synthesis and X-Ray Crystal Structure of a New Potent Pyrethroid Acid, (+/-)-cis-3--2,2-dimethylcyclopropanecarboxylic Acid
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Single-crystal X-ray analysis of the title compound has established its structure and molecular geometry.Crystals are monoclinic, space group P21/c, with a = 9.487(4), b = 8.009(4), c = 16.214(6) Angstroem, β = 119.91(1) deg, Z = 4.The structure was solved by direct methods and refined by full-matrix least-squares calculations to R 0.056 over 1242 reflections measured by diffractometer.The crystals contain centrosymmetric hydrogen-bonded dimers (O...O 2.65 Angstroem) in which the carboxy and vinyl substituents are in a 'bisecting' orientation, and the C=O group and one of hydrogen atoms on each methyl group point over the cyclopropane ring.The bond lengths in the ring reflect the substitution pattern.
- Engel, John F.,McPhail, Andrew T.,Miller, Richard W.
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p. 1737 - 1740
(2007/10/02)
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