Rice metallothionein-like protein (rgMT) shows characteristics of a three-section pattern composed of two highly conserved cysteine rich (CR) domains in the terminals and a spacer without cysteine (cys) residues in th...Rice metallothionein-like protein (rgMT) shows characteristics of a three-section pattern composed of two highly conserved cysteine rich (CR) domains in the terminals and a spacer without cysteine (cys) residues in the center of the molecule. In this paper, the two CR domains and the spacer region were modeled by the distance geometry and homology methods separately. For the CR domains, twenty random models were generated for each cys combination based on the constraint conditions of CXC (C represents cys, X represents any amino acid other than cys), and CXXC motifs and a metal-sulfur chelating cluster. Four models for the N-terminal and two for C-terminal CR domain containing metal chelating structures formed by different combinations of cys were selected from 900 possible conformations. The GOR method was used to predict the secondary structure of the spacer region and its model was built by the homology method. After three parts of the protein were modeled, they were connected to form a three-dimensional structure model of rgMT. The whole conformation showed that rgMT could form two independent metal-sulfur chelating structures connected by a spacer peptide, without a structural or energy barrier for them to form two independent metal-chelating clusters just as mammalian metallothionein (MT) proteins. As all plant metallothionein-like (MT-L) proteins have the same primary structural characteristic, two CR domains connected by a spacer region, and many have the same cys arrangement pattern as rgMT, the three-dimensional structure model of rgMT will provide an important reference for the structural study of other plant MT-L proteins.展开更多
With the progress of plant genome research, more than 50 plant metallothionein_like (MT_L) genes have been found, but only several MT_L proteins have been detected and no experimental structural information for MT_L p...With the progress of plant genome research, more than 50 plant metallothionein_like (MT_L) genes have been found, but only several MT_L proteins have been detected and no experimental structural information for MT_L proteins has been reported so far. Since detailed knowledge of the protein tertiary structure is required to understand its biological function, a method is needed to determine the structure of these proteins. In this study, the structural data of known mammal MT was used to determine the interatomic distance constraints of the CXC and CXXC motifs and the metal_sulfur chelating cluster. Then several possible MT conformations were predicted using a distance geometry algorithm. The statistical analysis was used to select those with much lower target function values and lower conformation energies as the predicted tertiary structural models of the cysteine_rich (CR) domains of these proteins. A suitable prediction method for modeling the CR domain of the plant MT_L protein was constructed. The accurately predicted result for the known structure of an MT protein from blue crab suggests that this method is practicable. The tertiary structures of CR domains of rape MT_L protein LSC54 was then modeled with this method.展开更多
试验旨在研究猪圆环病毒不同佐剂疫苗的制备及其对免疫原性的影响。将去除信号肽的PCV2(porcine circovirus type 2,PCV2)Cap蛋白基因连接在pET-28a载体上,进行诱导表达,用脱氧胆酸钠(DOC)和低浓度尿素对表达产物进行溶解,制备氢氧化铝...试验旨在研究猪圆环病毒不同佐剂疫苗的制备及其对免疫原性的影响。将去除信号肽的PCV2(porcine circovirus type 2,PCV2)Cap蛋白基因连接在pET-28a载体上,进行诱导表达,用脱氧胆酸钠(DOC)和低浓度尿素对表达产物进行溶解,制备氢氧化铝胶体佐剂、脂质体佐剂、弗氏佐剂、白油佐剂、蜂胶佐剂,并与纯化的PCV2-Cap蛋白混合制成亚单位疫苗,以商品化的灭活疫苗作为阳性对照,免疫小鼠,并使用ELISA方法检测动物血清中抗体及细胞因子含量的变化,评估其免疫保护效果。结果显示,表达产物以包涵体的形式存在,使用DOC溶解包涵体可省略蛋白复性步骤,且纯化方法简单,获得纯度较高的衣壳蛋白;ELISA检测结果表明PCV2-Cap蛋白能诱导产生特异性较高的抗体;水系佐剂制备的亚单位疫苗具有较高的免疫活性,为亚单位疫苗的商品化提供重要的数据支持。展开更多
Since a protein containing large amounts of sulphurand cadmium was isolated from horse kidney in 1957 andnamed metallothionein(MT)[1],more than 174 metal-lothioneins have been found in diverse organisms[2],Withthe pro...Since a protein containing large amounts of sulphurand cadmium was isolated from horse kidney in 1957 andnamed metallothionein(MT)[1],more than 174 metal-lothioneins have been found in diverse organisms[2],Withthe progress of plant genome research,many genes whichcould encode proteins similar to class I mammalian met-allothioneins were found in plants,and the produets ofthese genes have been customarily referred to as metal-lothionein-like(MT-L)protein or class I plant metal-lothioneins.展开更多
文摘Rice metallothionein-like protein (rgMT) shows characteristics of a three-section pattern composed of two highly conserved cysteine rich (CR) domains in the terminals and a spacer without cysteine (cys) residues in the center of the molecule. In this paper, the two CR domains and the spacer region were modeled by the distance geometry and homology methods separately. For the CR domains, twenty random models were generated for each cys combination based on the constraint conditions of CXC (C represents cys, X represents any amino acid other than cys), and CXXC motifs and a metal-sulfur chelating cluster. Four models for the N-terminal and two for C-terminal CR domain containing metal chelating structures formed by different combinations of cys were selected from 900 possible conformations. The GOR method was used to predict the secondary structure of the spacer region and its model was built by the homology method. After three parts of the protein were modeled, they were connected to form a three-dimensional structure model of rgMT. The whole conformation showed that rgMT could form two independent metal-sulfur chelating structures connected by a spacer peptide, without a structural or energy barrier for them to form two independent metal-chelating clusters just as mammalian metallothionein (MT) proteins. As all plant metallothionein-like (MT-L) proteins have the same primary structural characteristic, two CR domains connected by a spacer region, and many have the same cys arrangement pattern as rgMT, the three-dimensional structure model of rgMT will provide an important reference for the structural study of other plant MT-L proteins.
文摘With the progress of plant genome research, more than 50 plant metallothionein_like (MT_L) genes have been found, but only several MT_L proteins have been detected and no experimental structural information for MT_L proteins has been reported so far. Since detailed knowledge of the protein tertiary structure is required to understand its biological function, a method is needed to determine the structure of these proteins. In this study, the structural data of known mammal MT was used to determine the interatomic distance constraints of the CXC and CXXC motifs and the metal_sulfur chelating cluster. Then several possible MT conformations were predicted using a distance geometry algorithm. The statistical analysis was used to select those with much lower target function values and lower conformation energies as the predicted tertiary structural models of the cysteine_rich (CR) domains of these proteins. A suitable prediction method for modeling the CR domain of the plant MT_L protein was constructed. The accurately predicted result for the known structure of an MT protein from blue crab suggests that this method is practicable. The tertiary structures of CR domains of rape MT_L protein LSC54 was then modeled with this method.
文摘试验旨在研究猪圆环病毒不同佐剂疫苗的制备及其对免疫原性的影响。将去除信号肽的PCV2(porcine circovirus type 2,PCV2)Cap蛋白基因连接在pET-28a载体上,进行诱导表达,用脱氧胆酸钠(DOC)和低浓度尿素对表达产物进行溶解,制备氢氧化铝胶体佐剂、脂质体佐剂、弗氏佐剂、白油佐剂、蜂胶佐剂,并与纯化的PCV2-Cap蛋白混合制成亚单位疫苗,以商品化的灭活疫苗作为阳性对照,免疫小鼠,并使用ELISA方法检测动物血清中抗体及细胞因子含量的变化,评估其免疫保护效果。结果显示,表达产物以包涵体的形式存在,使用DOC溶解包涵体可省略蛋白复性步骤,且纯化方法简单,获得纯度较高的衣壳蛋白;ELISA检测结果表明PCV2-Cap蛋白能诱导产生特异性较高的抗体;水系佐剂制备的亚单位疫苗具有较高的免疫活性,为亚单位疫苗的商品化提供重要的数据支持。
基金The 863 Plan for Young ScientistState Key Basic Research and Development Plan(G1998010100)The FEEYT Foundation Trans-Century Training program from the ministry of education of china
文摘Since a protein containing large amounts of sulphurand cadmium was isolated from horse kidney in 1957 andnamed metallothionein(MT)[1],more than 174 metal-lothioneins have been found in diverse organisms[2],Withthe progress of plant genome research,many genes whichcould encode proteins similar to class I mammalian met-allothioneins were found in plants,and the produets ofthese genes have been customarily referred to as metal-lothionein-like(MT-L)protein or class I plant metal-lothioneins.
