Journal of Molecular Catalysis B-enzymatic最新文献_第9页

Biocatalytic study of novel oleate hydratases 新型油酸水合酶的生物催化研究

Journal of Molecular Catalysis B-enzymatic Pub Date : 2016-11-01 Epub Date: 2017-01-16 DOI: 10.1016/j.molcatb.2017.01.010

Jens Schmid , Lisa Steiner , Silvia Fademrecht, Jürgen Pleiss, Konrad B. Otte, Bernhard Hauer

{"title":"Biocatalytic study of novel oleate hydratases","authors":"Jens Schmid , Lisa Steiner , Silvia Fademrecht, Jürgen Pleiss, Konrad B. Otte, Bernhard Hauer","doi":"10.1016/j.molcatb.2017.01.010","DOIUrl":"10.1016/j.molcatb.2017.01.010","url":null,"abstract":"<div>The direct hydration of C<img>C bonds to yield alcohols or the reverse dehydration is chemically challenging but highly sought after. Recently, oleate hydratases (OAHs) gained attention as biocatalytic alternatives capable of hydrating isolated, non-activated C<img>C bonds. Their natural reaction is the conversion of oleic acid to (R)-10-hydroxystearic acid.In this work, we report the first comparative study of several OAHs. Therefore we established the Hydratase Engineering Database (HyED) comprising 2046 putative OAHs from eleven homologous families and selected nine homologs for cloning in E. coli. The heterologously expressed enzymes were evaluated concerning activity and substrate specificity. The enzymes have a broad substrate scope ranging from oleic acid (C18) to the novel synthetic substrate (Z)-undec-9-enoic acid (C11). The OAHs from Elizabethkingia meningoseptica and Chryseobacterium gleum showed the best expression, highest stability and broadest substrate scope, making them interesting candidates for directed evolution to engineer them for the application as general hydratase catalysts.</div>","PeriodicalId":16416,"journal":{"name":"Journal of Molecular Catalysis B-enzymatic","volume":"133 ","pages":"Pages S243-S249"},"PeriodicalIF":0.0,"publicationDate":"2016-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.molcatb.2017.01.010","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86285751","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 24

A comparative study of papain and bromelain in enzymatic oligomerization of l-Phe methyl ester in aqueous environment 木瓜蛋白酶和菠萝蛋白酶在水环境中酶促l-苯丙氨酸甲酯低聚的比较研究

Journal of Molecular Catalysis B-enzymatic Pub Date : 2016-11-01 Epub Date: 2016-12-05 DOI: 10.1016/j.molcatb.2016.12.001

Jianyun Yu , Feng Lin , Shengheng Lin , Xiaolin Pei , Jiang Miao , Xinxin Chen , Stephen Gang Wu , Anming Wang

{"title":"A comparative study of papain and bromelain in enzymatic oligomerization of l-Phe methyl ester in aqueous environment","authors":"Jianyun Yu , Feng Lin , Shengheng Lin , Xiaolin Pei , Jiang Miao , Xinxin Chen , Stephen Gang Wu , Anming Wang","doi":"10.1016/j.molcatb.2016.12.001","DOIUrl":"10.1016/j.molcatb.2016.12.001","url":null,"abstract":"<div>In this study, we developed an efficient approach for hydrophobic amino acids polymerization in aqueous solution. We compared the catalysis efficiency of papain and bromelain in catalyzing l-phenylalanine methyl ester (l-Phe-Me) for oligomer peptides synthesis. A set of reaction conditions (such as protease type, reaction temperature, time, and pH) have been tested for the polymerization reaction with papain and bromelain, respectively. Moreover, the resultant oligomers were analyzed through 1HNMR and MALDI-TOF. The results indicated that the average degree of polymerization (DP) reached the highest value (6.74) when papain was used for l-Phe-Me polymerization in phosphate buffer (0.2M, pH 8) at 40°C for three hours. At 50°C, the DP reached 6.62 with a yield of 72.9% when papain as the catalyst. Its yield and DP were 4.50 and 1.27 folds higher than those of the oligo- peptides synthesized by bromelain. Moreover, we found the DP and the yield of oligo(l-Phe) can be enhanced with higher reaction temperature and longer reaction time. In summary, papain presents better catalytic properties compared with bromelain for l-Phe polymerization in terms of DP and yield. Oligomerization catalyzed by papain at high temperature presents a potent procedure for the synthesis of biologically active oligo(l-Phe) peptides.</div>","PeriodicalId":16416,"journal":{"name":"Journal of Molecular Catalysis B-enzymatic","volume":"133 ","pages":"Pages S95-S99"},"PeriodicalIF":0.0,"publicationDate":"2016-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.molcatb.2016.12.001","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76651536","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 7

Determination of optimum conditions for glucose-6-phosphate dehydrogenase immobilization on chitosan-coated magnetic nanoparticles and its characterization 壳聚糖包覆磁性纳米颗粒固定化葡萄糖-6-磷酸脱氢酶最佳条件的确定及其表征

Journal of Molecular Catalysis B-enzymatic Pub Date : 2016-11-01 DOI: 10.1016/J.MOLCATB.2016.11.004

Selmihan Şahin, I. Ozmen

引用次数: 16

One-pot stereoselective synthesis of chiral 1, 3-oxathiolane by Trichosporon laibachii lipase: Optimization by response surface methodology integrated a desirability function approach 三叉线虫脂肪酶一锅立体选择性合成手性1,3 -草硫代烷:响应面法及期望函数优化

Journal of Molecular Catalysis B-enzymatic Pub Date : 2016-11-01 Epub Date: 2016-07-14 DOI: 10.1016/j.molcatb.2016.07.007

Yuanyuan Zhang, Xin Gao, Caiyun Wang, Zhenkun Zheng, Lulu Wang, Junhong Liu

{"title":"One-pot stereoselective synthesis of chiral 1, 3-oxathiolane by Trichosporon laibachii lipase: Optimization by response surface methodology integrated a desirability function approach","authors":"Yuanyuan Zhang, Xin Gao, Caiyun Wang, Zhenkun Zheng, Lulu Wang, Junhong Liu","doi":"10.1016/j.molcatb.2016.07.007","DOIUrl":"10.1016/j.molcatb.2016.07.007","url":null,"abstract":"<div>The asymmetric synthesis of chiral 1,3-oxathiolan-5-ones has attracted a great deal of attention owing to their broad biological activities and importance as intermediates for a range of useful pharmaceuticals. However, the enantiomeric purity of desired enantiomer was moderate while maintaining high yield. Here, high enantiomerically pure chiral 1,3-oxathiolane intermediate was synthesized by cyclization-acetylation reaction in organic media using immobilized Trichosporon laibachii (T. laibachii) lipase with one-pot process. Response surface methodology (RSM) integrated a desirability function approach was used to study and optimize the reaction conditions. The effects of several reaction parameters (initial water content of reaction medium, lipase amount and reaction temperature) on enantiomeric excess (ee) and the conversion of benzoyl aldehyde (C) were evaluated. The enzyme activity as well as enantioselectivity was markedly influenced by the initial water content of reaction medium and reaction temperature. The maximum overall desirability (D) of 0.958 was achieved at initial water content of 0.46%, lipase amount of 4.58% and reaction temperature 43 <!-->°C. The corresponding maximum ee and C were 94.33% and 97.40%, respectively. A good correlation between the predicted and actual responses showed that the generated model could adequately predict ee and C.</div>","PeriodicalId":16416,"journal":{"name":"Journal of Molecular Catalysis B-enzymatic","volume":"133 ","pages":"Pages 27-34"},"PeriodicalIF":0.0,"publicationDate":"2016-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.molcatb.2016.07.007","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73711103","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 11

Insight into the mechanism behind the activation phenomenon of lipase from Thermus thermophilus HB8 in polar organic solvents 研究嗜热热菌HB8脂肪酶在极性有机溶剂中的活化机制

Journal of Molecular Catalysis B-enzymatic Pub Date : 2016-11-01 Epub Date: 2017-03-08 DOI: 10.1016/j.molcatb.2017.03.002

Hao Cao , Kaili Nie , Haijun Xu , Xin Xiong , Rumen Krastev , Fang Wang , Tianwei Tan , Luo Liu

{"title":"Insight into the mechanism behind the activation phenomenon of lipase from Thermus thermophilus HB8 in polar organic solvents","authors":"Hao Cao , Kaili Nie , Haijun Xu , Xin Xiong , Rumen Krastev , Fang Wang , Tianwei Tan , Luo Liu","doi":"10.1016/j.molcatb.2017.03.002","DOIUrl":"10.1016/j.molcatb.2017.03.002","url":null,"abstract":"<div>A thermophilic lipase from Thermus thermophilus (lipaseTt) was heterologously overexpressed in Escherichia coli BL21(DE3). The tolerance of (lipaseTt) towards polar organic solvents and the associated activation phenomena were investigated. The catalytic efficiency (Kcat/KM) of lipaseTt in 56% DMSO was up to 25.64 times higher than that in phosphate buffer. Molecular dynamic (MD) simulations were carried out to investigate the activation mechanism of the lipaseTt by polar organic solvents. After refining the homology modeling of lipaseTt by using MD-simulation, a new secondary structure in the lid region indicates a rigid structure, corresponding to its nature of thermostability. Subsequently, the loss of a secondary structure of lipaseTt in the presence of polar organic solvent was observed in both MD-simulation and Circular dichroism spectra. The results of MD-simulation demonstrate that the overall structure maintained stable with or without polar organic solvent; however, the lid region was found more flexible in the presence of polar organic solvent. The flexible lid facilitates the substrate to access the catalytic site inside the lipase and the lipase displays enhanced activity in the presence of a polar organic solvent.</div>","PeriodicalId":16416,"journal":{"name":"Journal of Molecular Catalysis B-enzymatic","volume":"133 ","pages":"Pages S400-S409"},"PeriodicalIF":0.0,"publicationDate":"2016-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.molcatb.2017.03.002","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80327596","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 10

Computational insights into the oxidation of mono- and 1,4 disubstituted arenes by the Toluene Dioxygenase enzymatic complex 甲苯双加氧酶复合物氧化单和1,4二取代芳烃的计算见解

Journal of Molecular Catalysis B-enzymatic Pub Date : 2016-11-01 Epub Date: 2017-03-08 DOI: 10.1016/j.molcatb.2017.03.003

Ma. Agustina Vila , Diego Umpiérrez , Gustavo Seoane , Sonia Rodríguez , Ignacio Carrera , Nicolás Veiga

{"title":"Computational insights into the oxidation of mono- and 1,4 disubstituted arenes by the Toluene Dioxygenase enzymatic complex","authors":"Ma. Agustina Vila , Diego Umpiérrez , Gustavo Seoane , Sonia Rodríguez , Ignacio Carrera , Nicolás Veiga","doi":"10.1016/j.molcatb.2017.03.003","DOIUrl":"10.1016/j.molcatb.2017.03.003","url":null,"abstract":"<div>Toluene Dioxygenase (TDO) enzymatic complex has been widely used for preparation of enantiopure cis-cyclohexadienediols for synthetic applications. Along the last 30 years, a variety of mono- and di-substituted arenes have been studied as substrates for this enzyme, and some interesting observations have been reported regarding the yield and selectivity of the biotransformation. Nevertheless, none of them has been explained considering the active site’ structural and electronic features. In this work we present the first computational model of TDO’s active site, with a description of its architecture and interactions with the substrate to understand and predict substrate orientation. Our findings indicate that in the O2-free TDO, the iron(II) is stabilized by the coordination of an oxygen atom from the neighboring Gln215 residue. Besides, the active site is comprised by four pockets with different relative affinities for the substrates’ substituents. Monosubstituted arenes adopt a pose in which the alkyl chains maximize the London dispersion interactions with minimal steric clashes, giving an explanation for the observed trend in the benzylic hydroxylation yields. Finally, the computational results allowed us to rationalize the enantiomeric excess of 1,4-disubstituted arenes and the regioselectivity of the dihydroxylation of fluorobenzene. These data were used to develop and validate an affinity index (AI), as a quantitative indicator of the orientation preference for these substrates. This practical and easy-to-use tool can be applied to successfully predict the orientation of the para-disubstituted benzenes into the TDO active site.</div>","PeriodicalId":16416,"journal":{"name":"Journal of Molecular Catalysis B-enzymatic","volume":"133 ","pages":"Pages S410-S419"},"PeriodicalIF":0.0,"publicationDate":"2016-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.molcatb.2017.03.003","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87820126","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 5

A secreted Staphylococcus aureus lipase engineered for enhanced alcohol affinity for fatty acid esterification 一种分泌的金黄色葡萄球菌脂肪酶，用于增强乙醇对脂肪酸酯化的亲和力

Journal of Molecular Catalysis B-enzymatic Pub Date : 2016-11-01 Epub Date: 2016-11-18 DOI: 10.1016/j.molcatb.2016.11.013

Benjamin D. Saylor, John J. Love

{"title":"A secreted Staphylococcus aureus lipase engineered for enhanced alcohol affinity for fatty acid esterification","authors":"Benjamin D. Saylor, John J. Love","doi":"10.1016/j.molcatb.2016.11.013","DOIUrl":"https://doi.org/10.1016/j.molcatb.2016.11.013","url":null,"abstract":"<div>Presently the production and use of biodiesel is not cost-effective in comparison to traditional fossil fuels. Naturally occurring enzymes, such as lipases and esterases, can potentially be engineered to lower the cost of certain steps in the biodiesel synthesis process that would otherwise be more costly. However, these enzymes have evolved to perform biologically relevant functions, and not necessarily to manufacture biodiesel under commercially viable conditions. To this end, we have identified, cloned, expressed, purified, and characterized two proteins from the staphylococcal lipase family that are capable of catalyzing the formation of fatty acid alkyl esters. In an effort to explore strategies for improving these fatty acid modifying enzymes (FAMEs), we have engineered a chimeric fusion protein that significantly increases the esterification of free fatty acid with ethanol. The fusion protein, which consists of a staphylococcal FAME fused to a Drosophila ethanol binding protein, demonstrably improves the rate of catalysis by providing an additional substrate binding site and concomitant increase in the local concentration of substrate. This results in greater overall substrate (ethanol) residence in proximity to the catalytic domain, and a faster rate of catalysis, without the necessity of altering the amino acid sequence of the FAME protein.</div>","PeriodicalId":16416,"journal":{"name":"Journal of Molecular Catalysis B-enzymatic","volume":"133 ","pages":"Pages S44-S52"},"PeriodicalIF":0.0,"publicationDate":"2016-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.molcatb.2016.11.013","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91751883","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Enhanced catalytic efficiency of nitrilase from Acidovorax facilis 72W and application in bioconversion of 3-cyanopyridine to nicotinic acid Acidovorax装置72W硝化酶催化效率的提高及其在3-氰吡啶制烟酸生物转化中的应用

Journal of Molecular Catalysis B-enzymatic Pub Date : 2016-11-01 Epub Date: 2017-03-27 DOI: 10.1016/j.molcatb.2017.03.010

He Li , Weiliang Dong , Yue Zhang , Kuan Liu , Wenming Zhang , Min Zhang , Jiangfeng Ma , Min Jiang

{"title":"Enhanced catalytic efficiency of nitrilase from Acidovorax facilis 72W and application in bioconversion of 3-cyanopyridine to nicotinic acid","authors":"He Li , Weiliang Dong , Yue Zhang , Kuan Liu , Wenming Zhang , Min Zhang , Jiangfeng Ma , Min Jiang","doi":"10.1016/j.molcatb.2017.03.010","DOIUrl":"10.1016/j.molcatb.2017.03.010","url":null,"abstract":"<div>In this study, the catalytic efficiency using NitA from Acidovorax facilis 72W for nicotinic acid (NA) production was investigated and further improved by site-directed mutagenesis. Results showed that the specific activity of mutated NitA-C2 (F168V-S192F) towards 3-cyanopyridine increased 5-fold to 35Umg−1 protein. Further characterization of the biochemical properties of both nitrilases showed the optimal pH and temperature were 6.0–8.0 and 60°C, respectively, whereas the pH and thermal stability of NitA-C2 were decreased. Finally, whole cell catalysis was adopted for NA production and a 100% conversion yield was achieved under 0.1molL−1 3-cyanopyridine for both strains. Besides, the conversion rate by E. coli BL21 (DE3-pET-nitA-C2) reached to 1.0mmolmin−1 <!-->g−1 wet cell weight, which was 3-fold higher than that by E. coli BL21 (DE3-pET-nitA). These results indicated that the mutated NitA-C2 was a promising candidate which holds potential application in biological NA production.</div>","PeriodicalId":16416,"journal":{"name":"Journal of Molecular Catalysis B-enzymatic","volume":"133 ","pages":"Pages S459-S467"},"PeriodicalIF":0.0,"publicationDate":"2016-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.molcatb.2017.03.010","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83210280","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 8

Specificity of tyrosinase-catalyzed synthesis of theaflavins 酪氨酸酶催化合成茶黄素的特异性

Journal of Molecular Catalysis B-enzymatic Pub Date : 2016-11-01 Epub Date: 2017-04-05 DOI: 10.1016/j.molcatb.2017.03.009

Asako Narai-Kanayama, Aya Kawashima, Yuuka Uchida, Miho Kawamura, Tsutomu Nakayama

{"title":"Specificity of tyrosinase-catalyzed synthesis of theaflavins","authors":"Asako Narai-Kanayama, Aya Kawashima, Yuuka Uchida, Miho Kawamura, Tsutomu Nakayama","doi":"10.1016/j.molcatb.2017.03.009","DOIUrl":"10.1016/j.molcatb.2017.03.009","url":null,"abstract":"<div>This study kinetically characterized the mechanism of the enzymatic synthesis of theaflavins (TFs) from catechins by mushroom tyrosinase (EC 1.14.18.1). In reactions containing one of four catechins, (-)-epicatechin (EC), (-)-epigallocatechin (EGC), and their galloylated forms (ECg and EGCg), they were oxidized by tyrosinase with apparent KM values of 3.78, 5.55, 0.80, and 3.05mM, respectively, and with different consumption rates, of which EC was more than four times higher than those of the others. In reactions with binary combinations of catechins with tyrosinase, the synthesis of TF1 from EC and EGC occurred most efficiently, while the yields of mono- and di-galloylated TFs, TF2A, TF2B, and TF3, were low. Time-dependent changes in concentrations of the reactants suggested that the enzymatic oxidation of catechins and the subsequent non-enzymatic coupling redox reaction between the quinone derived from EC or ECg and the intact pyrogallol-type catechin (EGC or EGCg) proceeded concurrently. The latter reaction induced the rapid decrease of EGC and EGCg and it was remarkable for EGCg. So the efficiency of condensation of a pair of quinones from catechol- and pyrogallol-type catechins is restricted, critically influencing the yield of TFs. Using green tea extracts as mixtures of the four substrate catechins, tyrosinase produced TF1 most abundantly. Furthermore, a remarkable enhancement of production of TF2A and TF2B as well as TF1 was observed, when the initial concentration of EGCg was low. These results suggest that the catechin composition has an impact on yields of TFs.</div>","PeriodicalId":16416,"journal":{"name":"Journal of Molecular Catalysis B-enzymatic","volume":"133 ","pages":"Pages S452-S458"},"PeriodicalIF":0.0,"publicationDate":"2016-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.molcatb.2017.03.009","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83799091","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 11

Comparative analysis of point mutations on protein COOH terminal near surface and its hydrophobic core provide insights on thermostability of Bacillus Lipase LipJ 通过对蛋白COOH末端近表面及其疏水核心点突变的比较分析，对芽孢杆菌脂肪酶LipJ的热稳定性有了新的认识

Journal of Molecular Catalysis B-enzymatic Pub Date : 2016-11-01 Epub Date: 2017-04-02 DOI: 10.1016/j.molcatb.2017.04.001

Shelly Goomber, Nisha Chopra, Gursimran Kaur Bedi, Jagdeep Kaur

{"title":"Comparative analysis of point mutations on protein COOH terminal near surface and its hydrophobic core provide insights on thermostability of Bacillus Lipase LipJ","authors":"Shelly Goomber, Nisha Chopra, Gursimran Kaur Bedi, Jagdeep Kaur","doi":"10.1016/j.molcatb.2017.04.001","DOIUrl":"10.1016/j.molcatb.2017.04.001","url":null,"abstract":"<div>Amino acid composition, protein conformation, weak interactions are some of the factors determining protein stability. Two point mutants of Bacillus LipJ (Ala81Tyr and Asn166Tyr) were designed and generated for comparison. Residue Ala81 targeted for substitution was buried in protein core with 0% accessibility. On other hand, residue Asn166 at protein <img>COOH terminal was predicted to be located within αF helix near surface. Point variants Ala81Tyr and Asn166Tyr were generated by site directed mutagenesis. In comparison to native protein LipJ, point variant Ala81Tyr was observed to be more thermostable and demonstrated 1.6 times relative activity after 1h exposure at 50°C. However, point variant Asn166Tyr showed dramatic shift in its thermostability, specific activity and substrate specificity pattern compared to wild type LipJ. Asn166Tyr variant was found to remain stable for hours at 50°C. Specific activity of Asn166Tyr was 20% of parent enzyme. Substrate specificity of Asn166Tyr was significantly shifted to fatty acyl chains of shorter lengths. Homolog modelling predicted global vs local structure change to explain molecular basis of differential behavior of point variants Asn166Tyr and Ala81Tyr respectively.</div>","PeriodicalId":16416,"journal":{"name":"Journal of Molecular Catalysis B-enzymatic","volume":"133 ","pages":"Pages S482-S490"},"PeriodicalIF":0.0,"publicationDate":"2016-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.molcatb.2017.04.001","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83992784","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1