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Molecular Basis for Stereospecific Hydrolysis of Ethyl Mandelate by Thermophilic Esterase

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Chemical Research in Chinese Universities 2011年第5期27卷 841-844页

作者： ZHANG Guo-yan TAO Jin zheng liang-yu CAO Shu-gui Key Laboratory for Molecular Enzymology and Engineering Ministry of Education College of Chemistry Jilin University Changchun 130012 P. R. China

The stereospecific hydrolysis of mandelate can be effectively catalyzed by hyperthermophilic acylpeptide esterase APE 1547（Aeropyrum pernix esterase 1547）. APE 1547 used in this reaction showed a remarkable stereodi-scrimination in favour of R-mandelic acid（99% e.e.） with an enantiomeric ratio E〉200. The results of computer simulation are consistent with the experimental results. It can be inferred that the R-substrate adopted a binding mode productive of the reaction due to the formation of the hydrogen bond at the active site of APE 1547.

关键词： Hyperthermophilic acylpeptide esterase Biocatalyst Stereospecific hydrolysis Mandelic acid Computer simulation

Synthesis of (S)-N-(2-Ethyl-6-methylphenyl) alanine by Enzyme-catalyzed Resolution and Chemical Racemization

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Chemical Research in Chinese Universities 2009年第6期25卷 836-840页

作者： zheng liang-yu ZHANG Suo-qin LU Xiao-li CAO Shu-gui Key Laboratory for Molecular Enzymology and Engineering of Ministry of Education College of Chemistry Stomatological Hospital Jilin University Changchun 130021 P. R. China

A practical synthesis of （S）-N-（2-ethyl-6-methylphenyl）alanine, a key intermediate for （S）-metolachlor, was completed by means of lipase-catalyzed hydrolytic kinetic resolution and chemical racemization of the remaining ester. The effects of operating temperature and enzyme concentration on the activity and enantioselectivity of enzyme were initially studied, and it was found that the enantioselectivity of CAL-B towards the resolution was not high enough to obtain enantiomerically pure compound（E=12.1）. When diethyl ether（15%, volume fraction） was added in the reaction medium, the lipase gave an excellent enantioselectivity（E=117.8）, which is about 9.7-fold that in pure buffered aqueous solution. For overcoming the limitation of a maximum theoretical yield of 50%, the acid product was separated from the remaining ester by a simple extraction procedure and the remaining ester was racemized with aldehyde and acetic acid under microwave irradiation or conventional heating condition, The results show the microwave irradiation was more effective than the conventional heating method and gave the desired （R,S）-N-（2- ethyl-6-methylphenyl）alanine methyl ester a high yield（92%） with R/S=50/50 in 1 h.

关键词： Candida antarctica lipase B Resolution (S)-N-(2-Ethyl-6-methylphenyl)alanine Racemization

Analysis of a Critical Residue Determining Herbicide Efficiency Sensitivity in Carboxyltransferase Domain of Acetyl-CoA Carboxylase from Poaceae by Homology Modeling and Free Energy Simulation

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Chemical Research in Chinese Universities 2010年第5期26卷 816-821页

作者： TAO Jin ZHAO Bo TIAN Xue-mei zheng liang-yu CAO Shu-gui Key Laboratory for Molecular Enzymology and Engineering of Ministry of Education Jilin University Changchun 130021 P. R. China

Carboxyltransferase domain（CT） of acetyl-coenzyme A carboxylase（ACCase, EC 6.***.1.2） from a family of Poaceae is an important target of commercial herbicide APPs for controlling grass weed growth. As the abuse of APPs herbicides, the resistant ACCase due to the mutation of a single residue（Ile→Leu）, which is located in CT active site, is emergent in many populations and species of Poaceae. So it is urgent to understand the resistant mechanism so as to design new effect herbicides. Herein lies the complex of CT dimmer from Lolium rigidum and herbicide haloxyfop successfully constructed for wild type enzyme and Ile/Leu mutant, respectively, providing a basis for explaining the resistance from microscopic structure. Moreover, the binding free energy difference between wild type and mutant enzymes was predicted in good agreement with the known observation, and the various contributions to it were analyzed, by Molecular mechanics-Poisson-Boltzmann surface area（MM-PBSA） method. The results indicate the van der Waals interaction difference between the protein and inhibitor, -22.94 kJ/mol of CT wild type lower than that of mutant, is the major reason for resistance. Structure analysis further suggests that van der Waals interaction difference is originated from the steric hindrance between the side chain of mutated residue Leu and the chiral methyl group of haloxyfop. All these findings enhance the understanding of resistant mechanism of ACCase to herbicide by Ile/Leu mutation and provide an important clue for the rational design of high effective herbicides.

关键词： Molecular modeling Molecular dynamics Free energy calculation Herbicide resistance

Monitoring the Hydrolysis of Olive Oil Catalyzed by Lipase via Acid Value Detection

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Chemical Research in Chinese Universities 2007年第2期23卷 196-199页

作者： GAO Gui zheng liang-yu ZHANG Zuo-ming HAN Si-ping CAO Sui-gui Key Laboratory of Molecular Enzymology and Engineering of Ministry of Education Jilin University Changchun 130021 P. R. China

Hydrolysis of olive oil catalyzed by Candida lipolytica lipase was investigated. The relative concentration of the components in the product was determined by using high performance liquid chromatography（HPLC）. Furthermore, a novel rapid method to detect the hydrolytic process of olive oil was developed based on the relationship between the acid value and the relative concentration of the different components.

关键词： Lipase Hydrolysis Olive oil Glyeefide Acid value

Refolding and Purification of Yeast Acetyl-CoA Carboxylases CT Domain Expressed as Inclusion Bodies in Escherichia coli

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Chemical Research in Chinese Universities 2009年第5期25卷 690-694页

作者： YANG Xue-ying TAO Jin zheng liang-yu WANG Rui-jian ZHAO Ke CAO Shu-gui Key Laboratory for Molecular Enzymology and Engineering Ministry of Education Jilin University Changchun 130021 P. R. China

Acetyl-CoA carboxylase（ACCase） is a crucial enzyme in fatty acid synthesis, by regulating the first committed step in the process. Therefore, it is a potential target for the development of new compounds against obesity or as herbicides. The cDNA encoding yeast ACCase CT domains（YCTs） from Saccharvmyces cerevisiae was amplified by RT-PCR and inserted into the vector PET28a（＋） for bacterial expression of YCT fused to N-terminal His-tag（YCT-his6）. YCTs-his6 was expressed in Escherichia coli BL21（DE3） PLys as inclusion bodies, which was solubilized in 8 mol/L urea. Ni-agarose chromatography was used to purify the inclusion bodies under denaturing condition. Correct refolding was achieved via systematic dialysis to remove the denaturant gently in the presence of 0.5 mmol/L Triton X-100. The low concentration Triton X-100 was included in the refolding buffer to increase the solubilization and enhance dimeric formation of refolding proteins. The activity of the refolded YCT-his6 was 1.2 U/rag as measured in a spectrophotometric assay using malonyl-CoA as the substrate. To our knowledge, it is the first time that the bioactive YCT-his6 has been expressed successfully in E. coli and isolated from their inclusion bodies.

关键词： Carboxyltransferase domain Expression Inclusion body Refolding

Cloning, Expression and Purification of Wheat Acetyl-CoA Carboxylases CT Domain in E. coil

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Chemical Research in Chinese Universities 2008年第6期24卷 752-755页

作者： WANG Rui-jian YANG Xue-ying zheng liang-yu YANG Ye GAO Gui CAO Shu-gui Key Laboratory for Molecular Enzymology and Engineering of Ministry of Education Jilin University Changchun 130021 P. R. China College of Forestry Beihua University Jilin 132013 P. R. China

The entire gene of carboxyltransferase（CT） domain of acetyl-CoA carboxylase（ACCase） from Chinese Spring wheat（CSW） plastid was cloned firstly, and the 2.3 kb gene was inserted into PET28a^＋ vector and expressed in E. coil in a soluble state. The （His）6 fusion protein was identified by SDS-PAGE and Western blot. The recombinant protein was purified by affinity chromatography, and the calculated molecular mass（Mr） was 88000. The results of the sequence analysis indicate that the cloned gene（GeneBank accession No. EU124675） was a supplement and revision of the reported ACCase CT partial cDNA from Chinese Spring wheat plastid. The recombinant protein will be significant for us to investigate the recognizing mechanism between ACCase and herbicides, and further to screen new herbicides.

关键词： Chinese Spring wheat Acetyl-CoA carboxylase Carboxyltransferase(CT) domain Cloning Expression Purification

Synthesis and Herbicidal Activity of Novel Phenoxysulfonylureas Derivatives

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Chemical Research in Chinese Universities 2009年第5期25卷 648-652页

作者： ZHANG Xin-min zheng liang-yu GAO Jun-long LIU Qing-wen SUN Guo-dong QIN Lin ZHANG Suo-qin College of Chemistry Jilin University Changchun 130021 P. R. China Key Laboratory for Molecular Enzymology and Engineering of Ministry of Education Jilin University Changchun 130021 P. R. China

Thirteen novel phenoxysulfonylureas derivatives were synthesized, and their structures were confirmed by MS, NMR and element analysis. The herbicidal activity and structure-activity relationship were also investigated... 详细信息

关键词： Phenoxysulfonylurea Acetohydroxyacid synthase Herbicidal activity

Association of host plant growth and weed occurrence with armyworm(Mythimna separata) damage in corn fields

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Journal of Integrative Agriculture 2018年第7期17卷 1538-1544页

作者： ZHANG Kun-peng yu Zhi-hao JIANG Shi-xiong SUN De-wen HUI Jun-tao zheng yu-liang LI Xiao-zhen WANG Xing-yun WU Jun-xiang State Key Laboratory of Crop Stress Biology in Arid Areas/College of Plant Protection Northwest A&F UniversityYangling 712100P.R.China Anyang Institute of Technology Anyang 455000P.R.China Plant Protection and Quarantine Station of Sanyuan County Sanyuan 713800P.R.China Plant Protection and Quarantine Station of Lantian County Lantian 710500P.R.China Plant Protection and Quarantine Station of Chang'an District Chang'an 710100P.R.China zhengping Plant Protection Technology Limited Company Xi'an 710000P.R.China

To clarify association between armyworm（Mythimna separata） damage level and the corn growth and weed occurrence, we investigated corn plant height, stem diameter and vigor as well as weed coverage and biomass. The investigations were conducted at three locations of Shaanxi Province, China which were suffered seriously from armyworm. Significant correlations were found between the parameters analyzed. At stunted corn growth and presence of plenty of weeds, the armyworm damage tended to be heavy; oppositely, when corn grew well and weed density were low, armyworm harm was the minimal. Therefore, corn growing status and weed density can significantly affect armyworm damage level. Our results imply that promoting corn growth and timely removal of weeds are conducive to reducing armyworm occurrence.

关键词： Mythimna separata damage degree corn growth corn field weeds

Relaxed Stable Stability Technology for an Air-to-air Missile

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International Journal of Plant Engineering and Management 2012年第2期17卷 112-116页

作者： GUO zheng-yu liang Xiao-geng Luoyang Opto-Electro Technology Development Center Luoyang 471000 P. R. China

Relaxed Stable Stability （RSS） in an important part of the active control technology. It is a new way to raise the flying speed, distance and maneuverability of missile. Depth study of RSS technology plays an important role for the new concept missile design. This paper describes the detailed definition of RSS and its advantages, pres- ents the research status and prospects for its application in the design of new missiles.

关键词： missile active control technology relaxed stable stability new future missiles