共查询到19条相似文献，搜索用时 203 毫秒
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《科学中国人》2015,(26)
目的构建SLO原核表达质粒,重组蛋白的诱导表达并纯化。方法提取链霉菌溶血素O模板DNA,PCR法扩增slo基因。构建融合表达重组质粒p GEX-6p-1-slo和pet32a-tev-slo,将正确的重组质粒转化至大肠杆菌BL21和大肠杆菌BL21-DE3,使用异丙基硫代βD半乳糖苷(IPTG)诱导表达重组融合蛋白。采用亲和层析纯化重组蛋白,切除标签后,再通过亲和层析纯化,获取SLO重组蛋白。结果 PCR扩增出slo基因,基因片段(1700 bp)与理论一致。经SDSPAGE,蛋白质印迹显示重组蛋白相对分子质量为55 k Da,与数据库中的相对分子质量结果相符。结论成功构建了slo原核表达质粒,表达并纯化了SLO重组蛋白。 相似文献
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目的:扩增弓形虫SAG2基因,构建pGEX-4T-1-SAG2重组质粒,在大肠杆菌中表达。方法:设计并合成引物,经PCR法扩增SAG2基因序列,与pMD18-T载体连接,构建pMD18-T-SAG2质粒,经酶切鉴定、测序,与pGEX-4T-1载体连接,构建pGEX-4T-1-SAG2质粒。将重组质粒转入大肠杆菌诱导表达,进行SDS-PAGE和Western-blot鉴定。结果:扩增出约561bp的SAG2基因序列,成功构建pGEX-4T-1-SAG2质粒,并在大肠杆菌中得到高效表达,融合蛋白的表达量占菌体总蛋白的40%。SDS-PAGE电泳显示pGEX-4T-1-SAG2的融合蛋白的分子量约为45kd。Western-blot显示融合蛋白有良好的抗原性。结论表达质粒在大肠杆菌中得到高效表达,为进一步研究弓形虫病的诊断做好准备。 相似文献
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《科学中国人》2015,(26)
目的:构建Visfatin原核表达质粒,诱导表达并纯化重组人内脂素(Visfatin)。方法:从人LO2细胞中提取总RNA后,经RT-PCR法得到人Visfatin的c DNA序列,用以构建带HIS标签的Visfatin重组质粒。然后将重组质粒转化到大肠杆菌BL21中,用异丙基硫代-β-D-半乳糖苷(IPTG)诱导表达,用Ni柱亲和层析纯化融合蛋白。结果:PCR扩增出的目的基因片段为1600 bp左右,与理论大小一致。SDS-PAGE、Western blot、质谱分析数据证明了蛋白是Visfatin融合蛋白。结论:成功的表达并纯化得到带HIS标签的Visfatin融合蛋白。 相似文献
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厌氧真菌能够产生高比活力的纤维素酶,但由于对厌氧环境的生产条件要求严格,生长速度缓慢,并不适合规模生产。本研究将厌氧真菌内切型-β-葡聚糖酶基因af1与大肠杆菌表达载体pET-28a(+)连接,得到重组质粒pET-28a(+)-af1。以大肠杆菌BL21(DE3)为宿主,重组质粒转化后获得重组大肠杆菌BL21(DE3)/pET-28a(+)-af1。采用SDS-PAGE蛋白电泳对重组大肠杆菌的表达产物进行分析,在40 kDa附近得到与目的基因af1表达蛋白理论值相当的明显条带。AF1酶蛋白的最适pH为6.0,最适温度为45°C。重组大肠杆菌的摇瓶产酶试验结果显示:诱导培养18 h时,内切型-β-葡聚糖酶(CMC酶)活力可达410 U/mL。该项研究工作为进一步构建内切型-β-葡聚糖酶高产菌株奠定了良好的基础。 相似文献
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His-猪生长激素融合基因在大肠杆菌中的表达与纯化 总被引：1，自引：1，他引：1
将通过PCR技术改建并去除了信号肽的猪生长激素cDNA克隆入大肠杆菌表达载体pET-28a( ),构建出能利用Ni-NTAAgarose柱一步纯化表达产物的重组质粒pPGH020。探讨了大肠杆菌中重组猪生长激素的最佳表达条件和纯化方法,制备并纯化了兔抗pGH抗体。SDS鄄PAGE和Westernblot的分析结果表明,26.5kD处有包括His·Taq、thrombin位点序列和pGH序列的融合蛋白特异条带。凝胶扫描估测猪生长激素的表达量占大肠杆菌胞浆蛋白的17.3%左右。 相似文献
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本试验用VP1基因C末端与表达载体连接,转化到大肠杆菌中,经IPTG诱导表达,收集不同时间段的菌液进行SDS-PAGE,结果表明重组的VP1基因C末端蛋白在大肠杆菌中能高效表达,表达的目的蛋白分子量约为16kd,而且重组菌诱导裂解物可在16kd处看到一条特异的蛋白条带,与预期大小一致,阴性对照未出现表达条带,而且重组菌在IPTG终浓度为1mmoL/L诱导6 h时表达量最大。表达产物主要以包涵体的形式存在,提取和裂解包涵体后,进一步纯化表达的目的蛋白,可获得纯度达70%以上的目的蛋白。 相似文献
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溶藻弧菌铁调蛋白基因的克隆、表达及其特征分析 总被引：1，自引：0，他引：1
铁为一切有机体所必需。对铁摄取与利用的调控在细菌生长和铁毒性中起重要作用。在革兰氏阴性细菌中,铁摄取调节蛋白(Fur)主管铁的代谢。溶藻弧菌是人和海洋动物共感染的一种主要病原弧菌。本研究克隆表达了溶藻弧菌的fur基因,并分析了其相关特征。该基因序列全长994 bp,其中包含450 bp的开放读码框,编码150个氨基酸残基的蛋白,推导的相对分子量为16.78 kD.在编码序列的上下游,RBS序列-、10序列-、35序列和二个潜在的转录终止子分别得到确定,但没有发现存在于大肠杆菌fur基因中的"铁盒子"。氨基酸序列的中段从G46位至D104位,为高度保守区域,其中包括含组氨酸丰富铁结合模型(H3-D-H-L-V-C-L-D-C-G)。SDS-PAGE分析表明,fur基因可在大肠杆菌中大量表达,带His-Tag的重组融和蛋白经镍亲和层析得到纯化,Western-blot分析结果显示,Fur蛋白具有免疫反应性。为进一步研究Fur蛋白的结构与功能打下基础。 相似文献
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BackgroundDegP is a serine protease that specifically cleaves and refolds unfolding proteins in the periplasmic space of the cells. To date, there is no information regarding DegP from halophilic bacteria. Chromohalobacter salexigens BKL5 is a moderately halophilic bacterium that has the ability to grow in a media containing more than 15% salt. Therefore, the objectives of this work were to clone and overexpress DegP-encoding gene from C. salexigens BKL5 and characterize its biochemical properties.ResultsDegP-encoding gene was overexpressed in Escherichia coli BL21(DE3) CodonPlus in an active form. SDS-PAGE analysis showed that the molecular weight of the recombinant DegP was 45 kDa. Size-exclusion chromatography analysis suggested that recombinant DegP was present in two multimeric states, hexameric and dodecameric, with molecular weights of 297.9 and 579.12 kDa, respectively. Both conformations were enzymatically active when casein was used as substrate for enzymatic assay. Circular dichroism analysis showed that recombinant DegP was composed of 0.21–0.29 helical content, which was comparable to the helical content in the crystal structure of E. coli DegP. The basic/acidic residue ratio of recombinant DegP was 0.56, which was slightly higher than that of DegP from extreme halophiles (average, 0.45) but significantly lower than that of DegP from nonhalophiles (average, 0.94).ConclusionsRecombinant DegP from C. salexigens BKL5 showed proteolytic activity when β-casein was used as a substrate. In silico analysis indicated that recombinant DegP had characteristics similar to those of halophilic proteins depending on its amino acid composition. 相似文献
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The white spot syndrome virus (WSSV) is one of the deadly pathogens of penaeid shrimps and other crustaceans. The WSSV virion
consists of an enveloped rod-shaped nucleocapsid enclosing a large circular double stranded DNA genome of 305 Kb with 181
open reading frames. The two major structural genes, VP19 and VP28 were amplified from the genomic DNA of Chinese isolate
of WSSV and cloned in pUCm-T vector and sub cloned in pET-30a (+) vector. The expressions of genes inE. coli (BL21) were confirmed by SDS-PAGE analysis. The clones were sequenced, submitted to the gene bank and the Xiang Shan strain
of WSSV were compared with the previous reported sequence of WSSV of various regions which revealed that VP19 and VP28 gene
sequences had certain differences from the sequences of similar genes of the isolate already reported. The recombinant proteins
expressed, purified and characterized. 相似文献
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BackgroundThe acidic subunit of amarantin (AAC)—the predominant amaranth seed storage protein—has functional potential and its third variable region (VR) has been modified with antihypertensive peptides to improve this potential. Here, we modified the C-terminal in the fourth VR of AAC by inserting four VY antihypertensive peptides. This modified protein (AACM.4) was expressed in Escherichia coli. In addition, we also recombinantly expressed other derivatives of the amarantin protein. These include: unmodified amarantin acidic subunit (AAC); amarantin acidic subunit modified at the third VR with four VY peptides (AACM.3); and amarantin acidic subunit doubly modified, in the third VR with four VY peptides and in the fourth VR with the RIPP peptide (AACM.3.4).ResultsE. coli BL21-CodonPlus (DE3)-RIL was the most favorable strain for the expression of proteins. After 6 h of induction, it showed the best recombinant protein titer. The AAC and AACM.4 were obtained at higher titers (0.56 g/L) while proteins modified in the third VR showed lower titers: 0.44 g/L and 0.33 g/L for AACM.3 and AACM.3.4, respectively. As these AAC variants were mostly expressed in an insoluble form, we applied a refolding protocol. This made it possible to obtain all proteins in soluble form. Modification of the VR 4 improves the thermal stability of amarantin acidic subunit; AAC manifested melting temperature (Tm) at 34°C and AACM.4 at 37.2°C. The AACM.3 and AACM.3.4 did not show transition curves.ConclusionsModifications to the third VR affect the thermal stability of amarantin acidic subunit. 相似文献
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根据鸡白细胞介素18（IL-18）cDNA基因序列设计了1对特异性引物，应用RT-PCR技术，从脂多糖（lipopolysaccharide，LPS）刺激的我国地方品种萧山鸡原代鸡脾细胞中扩增并克隆鸡IL-18全长基因（Genbank accession，AY628648）。扩增片段全长591bp，共编码197个氨基酸的前体蛋白，其中含有表达完整功能蛋白所必需的起始密码子和终止密码子。该序列与国外报道的鸡IL-18全长基因核苷酸序列及推导的氨基酸序列的同源性为98．99％。只在引导序列中出现两个氨基酸残基的缺失，分子进化分析表明萧山鸡IL-18基因与火鸡以及家鸭基因形成一个独立的分支。将萧山鸡IL-18成熟蛋白序列插入pGEX-4T-2载体并在Ecoli中得到表达，获得45kD的GST-IL-18融合蛋白。经纯化后用于制备多克隆抗体。本研究对萧山鸡白细胞介素18的全长基因进行了克隆及表达，并对其分子进化进行了分析。为深入研究其功能奠定了基础。 相似文献