根据樟叶越桔Vaccinium dunalianum叶芽转录组测序实验获得的糖基转移酶Vd UGT1基因部分c DNA序列设计引物,采用RACE-PCR技术克隆了全长1 620 bp c DNA序列的Vd UGT1基因,包括1 398 bp c DNA序列的完整开放阅读框,推测编码由465个氨基...根据樟叶越桔Vaccinium dunalianum叶芽转录组测序实验获得的糖基转移酶Vd UGT1基因部分c DNA序列设计引物,采用RACE-PCR技术克隆了全长1 620 bp c DNA序列的Vd UGT1基因,包括1 398 bp c DNA序列的完整开放阅读框,推测编码由465个氨基酸残基组成、相对分子质量为50.89 k D的糖基转移酶Vd UGT1。序列分析表明,Vd UGT1理论等电点为5.53,负电荷残基(Asp+Glu)总数为53个,正电荷残基(Arg+Lys)总数为41个,不稳定系数为48.38,属于不稳定蛋白;其二级结构的主要构件为α-螺旋和随机卷曲,无跨膜结构域,属于亲水性蛋白质。Vd UGT1位于C末端含有尿嘧啶核苷二磷酸糖基转移酶所特有UDPGT功能域,推测与尿嘧啶核苷二磷酸糖的结合有关。该研究为后期Vd UGT1的异源表达和功能研究奠定了基础。展开更多
Objective： Hepatocellular carcinoma （HCC） is a complex disease which associates with both environmental and genetic factors. The purpose of this study was to investigate whether the genetic polymorphisms of UDP-glu...Objective： Hepatocellular carcinoma （HCC） is a complex disease which associates with both environmental and genetic factors. The purpose of this study was to investigate whether the genetic polymorphisms of UDP-glucuronosyltransferase（UGT1A7）, an important phase II biotransformation enzyme, and X-ray repair cross-complementing group 1（XRCC1）, a pivotal DNA-repair gene, were related to the risk of HCC in Northeast China. Methods： One hundred and thirty six HCC patients and one hundred and thirty six frequency-matched controls were included in this hospital-based case-control study. Genotypes of UGT1A7 and XRCC1 were determined using allele-specific polymerase chain reaction （AS-PCR） and PCR-restriction fragment length polymorphism （RFLP）, and for which the odds ratio （OR） with 95% confidence interval （95% CI） were calculated. Results： The proportion of UGT1A7 low enzymatic allele （＊2 or ＊3） was higher in HCC patients than those in controls. The UGT1A7＊1/＊2 and ＊3/＊3 genotypes were associated with higher HCC risk （OR=2.09, 95%CI： 1.10-3.97; OR=5.67, 95%CI： 1.76-18.30, respectively）. The XRCC1 codon 399 Arg/Gln genotype could also elevate HCC risk （OR=2.16, 95% CI 1.29-3.61）. In addition to polymorphisms of UGT1A7 and XRCC1, multivariate logistic regression analysis demonstrated that other significant independent factors associated with HCC were HBV infection （OR=68.07, 95%CI： 28.03-165.26）, HCV infection （OR=30.97, 95%CI： 8.06-118.94） and family history of HCC （OR=10.62, 95%CI： 2.22-50.77）. Conclusion： The study shows that the polymorphisms of UGT1A7 and XRCC1 are associated with HCC risk. Determination of the polymorphisms of UGT1A7 and XRCC1 may provide an important clue to preventive measure against HCC.展开更多
Ginsenosides, the main pharmacologically active natural compounds in ginseng （Panax ginseng）, are mostly the glycosylated products of protopanaxadiol （PPD） and protopanaxatriol （PPT）. No uridine diphosphate glyc...Ginsenosides, the main pharmacologically active natural compounds in ginseng （Panax ginseng）, are mostly the glycosylated products of protopanaxadiol （PPD） and protopanaxatriol （PPT）. No uridine diphosphate glycosyltransferase （UGT）, which catalyzes PPT to produce PPT-type ginsenosides, has yet been reported. Here, we show that UGTPgl, which has been demonstrated to regio-specifically glycosylate the C20-OH of PPD, also specifically glycosylates the C20-OH of PPT to produce bioactive ginsenoside FI. We report the characterization of four novel UGT genes isolated from P. ginseng, sharing high deduced amino acid identity （〉84%） with UGTPgl. We demonstrate that UGTPgl00 specifically glycosylates the C6-OH of PPT to produce bioactive ginsenoside Rhl, and UGTPgl01 catalyzes PPT to produce F1, followed by the generation of ginsenoside Rgl from FI. However, UGTPgl02 and UGTPgl03 were found to have no detectable activity on PPT. Through structural modeling and site-directed mutagenesis, we identified several key amino acids of these UGTs that may play important roles in determining their activities and substrate regio-specificities. Moreover, we constructed yeast recombinants to biosynthesize F1 and Rhl by introducing the genetically engineered PPT-producing pathway and UGTPgl or UGTPgl00. Our study reveals the possible biosynthetic pathways of PPT-type ginsenosides in Panax plants, and provides a sound manufacturing approach for bioactive PPT-type ginsenosides in yeast via synthetic biology strategies.展开更多
The present study was designed to perform structural modifications of of neobavaisoflavone(NBIF), using an in vitro enzymatic glycosylation reaction, in order to improve its water-solubility. Two novel glucosides of N...The present study was designed to perform structural modifications of of neobavaisoflavone(NBIF), using an in vitro enzymatic glycosylation reaction, in order to improve its water-solubility. Two novel glucosides of NBIF were obtained from an enzymatic glycosylation by UDP-glycosyltransferase. The glycosylated products were elucidated by LC-MS, HR-ESI-MS, and NMR analysis. The HPLC peaks were integrated and the concentrations in sample solutions were calculated. The MTT assay was used to detect the cytotoxic activity of compounds in cancer cell lines. Based on the spectroscopic analyses, the two novel glucosides were identified as neobavaisoflavone-4′-O-β-D-glucopyranoside(1) and neobavaisoflavone-4′, 7-di-O-β-D-glucopyranoside(2). Additionally, the water-solubilities of compounds 1 and 2 were approximately 175.1-and 4 031.9-fold higher than that of the substrate, respectively. Among the test compounds, only NBIF exhibited weak cytotoxicity against four human cancer cell lines, with IC50 values ranging from 63.47 to 72.81 μmol·L^(-1). These results suggest that in vitro enzymatic glycosylation is a powerful approach to structural modification, improving water-solubility.展开更多
文摘根据樟叶越桔Vaccinium dunalianum叶芽转录组测序实验获得的糖基转移酶Vd UGT1基因部分c DNA序列设计引物,采用RACE-PCR技术克隆了全长1 620 bp c DNA序列的Vd UGT1基因,包括1 398 bp c DNA序列的完整开放阅读框,推测编码由465个氨基酸残基组成、相对分子质量为50.89 k D的糖基转移酶Vd UGT1。序列分析表明,Vd UGT1理论等电点为5.53,负电荷残基(Asp+Glu)总数为53个,正电荷残基(Arg+Lys)总数为41个,不稳定系数为48.38,属于不稳定蛋白;其二级结构的主要构件为α-螺旋和随机卷曲,无跨膜结构域,属于亲水性蛋白质。Vd UGT1位于C末端含有尿嘧啶核苷二磷酸糖基转移酶所特有UDPGT功能域,推测与尿嘧啶核苷二磷酸糖的结合有关。该研究为后期Vd UGT1的异源表达和功能研究奠定了基础。
基金supported by the grant from Department of Education of Liaoning Province, China (No. 2008S232)
文摘Objective： Hepatocellular carcinoma （HCC） is a complex disease which associates with both environmental and genetic factors. The purpose of this study was to investigate whether the genetic polymorphisms of UDP-glucuronosyltransferase（UGT1A7）, an important phase II biotransformation enzyme, and X-ray repair cross-complementing group 1（XRCC1）, a pivotal DNA-repair gene, were related to the risk of HCC in Northeast China. Methods： One hundred and thirty six HCC patients and one hundred and thirty six frequency-matched controls were included in this hospital-based case-control study. Genotypes of UGT1A7 and XRCC1 were determined using allele-specific polymerase chain reaction （AS-PCR） and PCR-restriction fragment length polymorphism （RFLP）, and for which the odds ratio （OR） with 95% confidence interval （95% CI） were calculated. Results： The proportion of UGT1A7 low enzymatic allele （＊2 or ＊3） was higher in HCC patients than those in controls. The UGT1A7＊1/＊2 and ＊3/＊3 genotypes were associated with higher HCC risk （OR=2.09, 95%CI： 1.10-3.97; OR=5.67, 95%CI： 1.76-18.30, respectively）. The XRCC1 codon 399 Arg/Gln genotype could also elevate HCC risk （OR=2.16, 95% CI 1.29-3.61）. In addition to polymorphisms of UGT1A7 and XRCC1, multivariate logistic regression analysis demonstrated that other significant independent factors associated with HCC were HBV infection （OR=68.07, 95%CI： 28.03-165.26）, HCV infection （OR=30.97, 95%CI： 8.06-118.94） and family history of HCC （OR=10.62, 95%CI： 2.22-50.77）. Conclusion： The study shows that the polymorphisms of UGT1A7 and XRCC1 are associated with HCC risk. Determination of the polymorphisms of UGT1A7 and XRCC1 may provide an important clue to preventive measure against HCC.
文摘Ginsenosides, the main pharmacologically active natural compounds in ginseng （Panax ginseng）, are mostly the glycosylated products of protopanaxadiol （PPD） and protopanaxatriol （PPT）. No uridine diphosphate glycosyltransferase （UGT）, which catalyzes PPT to produce PPT-type ginsenosides, has yet been reported. Here, we show that UGTPgl, which has been demonstrated to regio-specifically glycosylate the C20-OH of PPD, also specifically glycosylates the C20-OH of PPT to produce bioactive ginsenoside FI. We report the characterization of four novel UGT genes isolated from P. ginseng, sharing high deduced amino acid identity （〉84%） with UGTPgl. We demonstrate that UGTPgl00 specifically glycosylates the C6-OH of PPT to produce bioactive ginsenoside Rhl, and UGTPgl01 catalyzes PPT to produce F1, followed by the generation of ginsenoside Rgl from FI. However, UGTPgl02 and UGTPgl03 were found to have no detectable activity on PPT. Through structural modeling and site-directed mutagenesis, we identified several key amino acids of these UGTs that may play important roles in determining their activities and substrate regio-specificities. Moreover, we constructed yeast recombinants to biosynthesize F1 and Rhl by introducing the genetically engineered PPT-producing pathway and UGTPgl or UGTPgl00. Our study reveals the possible biosynthetic pathways of PPT-type ginsenosides in Panax plants, and provides a sound manufacturing approach for bioactive PPT-type ginsenosides in yeast via synthetic biology strategies.
基金financially supported by National Natural Science Foundation of China(No.81302671)the Education Department of Anhui Natural Science Research Project China(No.KJ2015A273)Zhejiang Provincial Natural Science Foundation of China(No.LY13H10004)
文摘The present study was designed to perform structural modifications of of neobavaisoflavone(NBIF), using an in vitro enzymatic glycosylation reaction, in order to improve its water-solubility. Two novel glucosides of NBIF were obtained from an enzymatic glycosylation by UDP-glycosyltransferase. The glycosylated products were elucidated by LC-MS, HR-ESI-MS, and NMR analysis. The HPLC peaks were integrated and the concentrations in sample solutions were calculated. The MTT assay was used to detect the cytotoxic activity of compounds in cancer cell lines. Based on the spectroscopic analyses, the two novel glucosides were identified as neobavaisoflavone-4′-O-β-D-glucopyranoside(1) and neobavaisoflavone-4′, 7-di-O-β-D-glucopyranoside(2). Additionally, the water-solubilities of compounds 1 and 2 were approximately 175.1-and 4 031.9-fold higher than that of the substrate, respectively. Among the test compounds, only NBIF exhibited weak cytotoxicity against four human cancer cell lines, with IC50 values ranging from 63.47 to 72.81 μmol·L^(-1). These results suggest that in vitro enzymatic glycosylation is a powerful approach to structural modification, improving water-solubility.
