An Amorpha fruticosa cDNA encoding 4 coumarate:CoA ligase (4CL), a key enzyme of phenylpropanoid metabolism related to lignin forming, was cloned by degenerating oligo primed polymerase chain reaction (PCR) and ...An Amorpha fruticosa cDNA encoding 4 coumarate:CoA ligase (4CL), a key enzyme of phenylpropanoid metabolism related to lignin forming, was cloned by degenerating oligo primed polymerase chain reaction (PCR) and rapid amplification of cDNA end (RACE) PCR. We designed 5′RACE primers based on 4CLA1 fragment which obtained from degenerate PCR. Inverse PCR and nested PCR enabled cloning of the remainder fragments of the gene included 5′ and 3′ end sequence. The ORF encodes a polypeptide of 540 amino acids. The predicted amino acid sequence exhibits significant homology with those of other cloned 4CL genes, contain domains typical of predicted 4CL proteins, in particular a postulated AMP binding site, catalytic domain, and conserved Cys residues.展开更多
In order to investigate the enzymatic properties of the 4CL1 of Populus tomentosa, the recombinant expression vector pQE31-4CL 1 was constructed. The recombinant was identified by three restriction endonucleases, then...In order to investigate the enzymatic properties of the 4CL1 of Populus tomentosa, the recombinant expression vector pQE31-4CL 1 was constructed. The recombinant was identified by three restriction endonucleases, then the vector pQE31-4CL 1 was transformed into expression host M15 （pREP4） and induced by isopropyl-a-D-thiogalactoside （IPTG） to express 60 kD fused protein Pt4CL1. The biologically active Pt4CL1, expressed as soluble protein, was achieved with 0.6 mmol＇L-1 IPTG induction as the expression temperature declined from 37 to 28℃. The 6-His tag facilitates affinity binding to Ni^2＋-nitrolotriacetic acid （NTA） and enables one-step purification to acquire the molecular SDS-PAGE electrophoresis purity of the active 4CL1 protein by agarose coupled with Ni^2＋-NTA affinity chromatography. The optimal substrate for Pt4CL 1 was 4-coumarate.展开更多
4-Coumarate ： coenzyme A Ilgase （4CL） Is one of the key enzymes In phenylpropanoid metabolism leading to series of phenollcs, Including water-soluble phenolic acids, which are important compounds determining the me...4-Coumarate ： coenzyme A Ilgase （4CL） Is one of the key enzymes In phenylpropanoid metabolism leading to series of phenollcs, Including water-soluble phenolic acids, which are important compounds determining the medicinal quality of Danshen （Salvia miltiorrhiza Bunge）, a traditional Chinese medicinal herb. To Investigate the function of 4CL in the biosynthesis of water-soluble phenolic acid in Danshen, we have cloned two cDNAs （Sm4CL1 and Sm4CL2） encoding divergent 4CL members by applying nested reverse transcrlptlon-polymerase chain reaction （RT-PCR） with degenerate primers followed by 5′/3′rapid amplification of cDNA ends （RACE） （Note, these sequence data have been submitted to the GenBank database under accession numbers AY237163 and AY237164）. Either of the coding regions was inserted into a pRSET vector and a kinetic assay was performed with purified recombinant proteins. The substrate utilization profile of Sm4CL1 was distinct from that of Sm4CL2. The Km values of Sm4CL1 and Sm4CL2 to 4-coumarlc acid were （72.20±4.10） and （6.50±1.45） μmol/L, respectively. These results, In conjunction with Northern blotting and other information, imply that Sm4CL2 may play an Important role in the biosynthesis of watersoluble phenolic compounds, whereas Sm4CL1 may play a minor role in the pathway. Southern blotting analysis suggested that both Sm4CL1 and Sm4CL2 genes are present as a single copy and are located at different sites In the genome.展开更多
大豆孢囊线虫是大豆产区病虫害防治策略的重要目标之一,大豆孢囊线虫的防控也一直是线虫领域研究热点之一。大豆孢囊线虫侵染不仅会造成大豆地下部分损伤,也使得地上部分受损从而影响其产量,因此需对大豆孢囊线虫的抗性机制进行分析以...大豆孢囊线虫是大豆产区病虫害防治策略的重要目标之一,大豆孢囊线虫的防控也一直是线虫领域研究热点之一。大豆孢囊线虫侵染不仅会造成大豆地下部分损伤,也使得地上部分受损从而影响其产量,因此需对大豆孢囊线虫的抗性机制进行分析以达到防控的目的。大豆孢囊线虫成功寄生宿主植物需对其细胞壁进行降解融合,形成为其生长发育提供唯一营养来源的合胞体。而阻碍大豆孢囊线虫移动和合胞体建立的细胞壁抗性是大豆抵御大豆孢囊线虫的关键,其中木质素是细胞壁发挥抗性的重要成分。木质素的生物合成主要包括莽草酸代谢途径、苯丙烷代谢途径和木质素合成的特异途径,4-香豆酸辅酶A连接酶(4-coumarate-Coenzyme A ligase,4CL)作为连接苯丙烷代谢途径和木质素特异合成途径的重要转折酶,决定了木质素的合成,其很可能是响应大豆孢囊线虫胁迫的重要调控因子。本文从线虫入侵需要细胞壁降解融合建立合胞体出发,围绕木质素导致的细胞壁抗性展开讨论,分析了4CL在细胞壁抗性中的响应机制,为进一步探索大豆孢囊线虫胁迫机制提供科学依据。展开更多
构建了携带紫穗槐尿苷二磷酸葡萄糖焦磷酸化酶(UDP-glucose pyrophosphorylase,UGPase)基因和4-香豆酸:辅酶A连接酶(4-coumarate:coenzyme A ligase,4CL)反义基因的双价基因植物表达载体,用热激法转化至根癌农杆菌LBA4404中,并用制备的...构建了携带紫穗槐尿苷二磷酸葡萄糖焦磷酸化酶(UDP-glucose pyrophosphorylase,UGPase)基因和4-香豆酸:辅酶A连接酶(4-coumarate:coenzyme A ligase,4CL)反义基因的双价基因植物表达载体,用热激法转化至根癌农杆菌LBA4404中,并用制备的农杆菌工程菌进行了烟草转化。PCR及Southern杂交结果证实,双价基因已成功整合到烟草基因组中。综纤维素和硫酸木质素含量测定结果显示,转基因烟草纤维素含量增加,木质素含量减少,表明双价基因能够有效表达。展开更多
文摘An Amorpha fruticosa cDNA encoding 4 coumarate:CoA ligase (4CL), a key enzyme of phenylpropanoid metabolism related to lignin forming, was cloned by degenerating oligo primed polymerase chain reaction (PCR) and rapid amplification of cDNA end (RACE) PCR. We designed 5′RACE primers based on 4CLA1 fragment which obtained from degenerate PCR. Inverse PCR and nested PCR enabled cloning of the remainder fragments of the gene included 5′ and 3′ end sequence. The ORF encodes a polypeptide of 540 amino acids. The predicted amino acid sequence exhibits significant homology with those of other cloned 4CL genes, contain domains typical of predicted 4CL proteins, in particular a postulated AMP binding site, catalytic domain, and conserved Cys residues.
文摘In order to investigate the enzymatic properties of the 4CL1 of Populus tomentosa, the recombinant expression vector pQE31-4CL 1 was constructed. The recombinant was identified by three restriction endonucleases, then the vector pQE31-4CL 1 was transformed into expression host M15 （pREP4） and induced by isopropyl-a-D-thiogalactoside （IPTG） to express 60 kD fused protein Pt4CL1. The biologically active Pt4CL1, expressed as soluble protein, was achieved with 0.6 mmol＇L-1 IPTG induction as the expression temperature declined from 37 to 28℃. The 6-His tag facilitates affinity binding to Ni^2＋-nitrolotriacetic acid （NTA） and enables one-step purification to acquire the molecular SDS-PAGE electrophoresis purity of the active 4CL1 protein by agarose coupled with Ni^2＋-NTA affinity chromatography. The optimal substrate for Pt4CL 1 was 4-coumarate.
基金Supported by the National Natural Science Foundation of China （30300447）.The authors thank Dr Chen Yongning （China Innovation Centre for Drug Development, HK） for useful suggestions and support. The authors also thank to Dr Fanya Zeng and Miss Charis Chan （Department of Zoology, University of Hong Kong） for technical assistance.
文摘4-Coumarate ： coenzyme A Ilgase （4CL） Is one of the key enzymes In phenylpropanoid metabolism leading to series of phenollcs, Including water-soluble phenolic acids, which are important compounds determining the medicinal quality of Danshen （Salvia miltiorrhiza Bunge）, a traditional Chinese medicinal herb. To Investigate the function of 4CL in the biosynthesis of water-soluble phenolic acid in Danshen, we have cloned two cDNAs （Sm4CL1 and Sm4CL2） encoding divergent 4CL members by applying nested reverse transcrlptlon-polymerase chain reaction （RT-PCR） with degenerate primers followed by 5′/3′rapid amplification of cDNA ends （RACE） （Note, these sequence data have been submitted to the GenBank database under accession numbers AY237163 and AY237164）. Either of the coding regions was inserted into a pRSET vector and a kinetic assay was performed with purified recombinant proteins. The substrate utilization profile of Sm4CL1 was distinct from that of Sm4CL2. The Km values of Sm4CL1 and Sm4CL2 to 4-coumarlc acid were （72.20±4.10） and （6.50±1.45） μmol/L, respectively. These results, In conjunction with Northern blotting and other information, imply that Sm4CL2 may play an Important role in the biosynthesis of watersoluble phenolic compounds, whereas Sm4CL1 may play a minor role in the pathway. Southern blotting analysis suggested that both Sm4CL1 and Sm4CL2 genes are present as a single copy and are located at different sites In the genome.
文摘大豆孢囊线虫是大豆产区病虫害防治策略的重要目标之一,大豆孢囊线虫的防控也一直是线虫领域研究热点之一。大豆孢囊线虫侵染不仅会造成大豆地下部分损伤,也使得地上部分受损从而影响其产量,因此需对大豆孢囊线虫的抗性机制进行分析以达到防控的目的。大豆孢囊线虫成功寄生宿主植物需对其细胞壁进行降解融合,形成为其生长发育提供唯一营养来源的合胞体。而阻碍大豆孢囊线虫移动和合胞体建立的细胞壁抗性是大豆抵御大豆孢囊线虫的关键,其中木质素是细胞壁发挥抗性的重要成分。木质素的生物合成主要包括莽草酸代谢途径、苯丙烷代谢途径和木质素合成的特异途径,4-香豆酸辅酶A连接酶(4-coumarate-Coenzyme A ligase,4CL)作为连接苯丙烷代谢途径和木质素特异合成途径的重要转折酶,决定了木质素的合成,其很可能是响应大豆孢囊线虫胁迫的重要调控因子。本文从线虫入侵需要细胞壁降解融合建立合胞体出发,围绕木质素导致的细胞壁抗性展开讨论,分析了4CL在细胞壁抗性中的响应机制,为进一步探索大豆孢囊线虫胁迫机制提供科学依据。
文摘构建了携带紫穗槐尿苷二磷酸葡萄糖焦磷酸化酶(UDP-glucose pyrophosphorylase,UGPase)基因和4-香豆酸:辅酶A连接酶(4-coumarate:coenzyme A ligase,4CL)反义基因的双价基因植物表达载体,用热激法转化至根癌农杆菌LBA4404中,并用制备的农杆菌工程菌进行了烟草转化。PCR及Southern杂交结果证实,双价基因已成功整合到烟草基因组中。综纤维素和硫酸木质素含量测定结果显示,转基因烟草纤维素含量增加,木质素含量减少,表明双价基因能够有效表达。
