Product Description
Recombinant 2019-nCoV Helicase is produced by our E.coli expression system and the target gene encoding Ala1-Gln601 is expressed with a 6His tag at the C-terminus.
Background:The non—structural protein 13 (nsp13) of SARS—CoV 2 is a helicase that separates double—stranded RNA or DNA with a 5"—3" polarity, using the energy of nucleotide hydrolysis. A basic biochemical characterization of nsp13 demonstrated that it can unwind both doublestranded DNA and RNA in a 5’-3’ direction, and it can hydrolyze all deoxyribonucleotide and ribonucleotide triphosphates. Helicases are motor proteins that utilize the energy derived from nucleotide hydrolysisto unwind double-stranded nucleic acids into two single-stranded nucleic acids. Initially, helicases were only thought to be molecular engines that unwind nucleic acids during replication, recombination, and DNA repair. Recent studies have shown that they are also involved in other biological processes, including displacement of proteins from nucleic acid, movement of Holliday junctions, chromatin remodeling, catalysis of nucleic acid conformational changes, several aspects of RNA metabolism, including transcription, mRNA splicing, mRNA export, translation, RNA stability and mitochondrial gene expression. Some human diseases, including Bloom’s syndrome, Werner’s syndrome, and Xeroderma Pigmentosum have been associated with defects in helicase function.Formulation:Supplied as a 0.2 μm filtered solution of PBS, 10% Glycerol, pH 7.4.Purity:> 90 % as determined by reducing SDS-PAGE.Endotoxin:< 1.0 EU per µg as determined by the LAL method.Shipping:This product is provided as liquid. It is shipped at frozen temperature with blue ice/gel packs. Upon receipt, store it immediately at<-20°C. Avoid freeze-thaw cycles.
More Details:Sequence:Ala1-Gln601Fusion Tag:C-6HisAccession:YP_009725308.1Species:VirusExpression System:E. coliMol Mass:70 kDaAP Mol Mass:70 kDaSynonyms:SARS-CoV 2 Helicase; SARS-CoV 2 nsp13Datasheet
FOR RESEARCH USE ONLY, NOT FOR USE IN DIAGNOSTIC PROCEDURES.Manufactured by: Elabscience
Questions about this product? Ready to place an order? Email us atorders@iwai-chem.comor give us a call: (650) 486-1541 |
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最好能说得具体点，小弟对此几乎一窍不通
谢谢
【教学内容一】分段盐析法，凝胶过滤法(盐析法概念及原理，分段盐析概念，分子筛效应，柱层析基本技术)
【实验原理】1.盐析法是一种利用蛋白质在高盐溶液中溶解度不同而分离的方法。通过将硫酸铵加入蛋白质溶液中，使蛋白质表面电荷被中和，水化膜被破坏，导致蛋白质在水溶液中的稳定性因素去除而沉淀。2.通过分段改变盐类浓度达到分离目的的方法叫分段盐析法。3.凝胶过滤又称分子筛层析。混合物随流动相流经装有凝胶作为固定相的层析柱时，分子量大的物质因不能进入凝胶网孔而沿凝胶颗粒间的空隙先被洗脱(阻力小,流程短,流速大),分子量小的物质因能进入凝胶网孔而受阻滞,流速缓慢,流程长而后被洗脱,由于流速不同可以把大小不同的分子分开.
【仪器与试剂】1.离心机2.真空泵3.饱和硫酸铵溶液：称取767g固体硫酸铵，加入1000ml水中，加热使之溶解，室温冷却后4℃静置过夜，然后用氨水将pH调至中性。4.固体(NH4)2SO45.SephadexG—256.奈氏试剂7.双缩脲试剂8.pH7.4,0.05MPBS
【步骤】
一分段盐析
1.观看人血清抗胰蛋白酶(α1-AT)的分离及鉴定教学录像2.每组量取20ml血清，倒入一干净烧杯中，缓慢加入饱和硫酸铵20ml，边加边搅拌,放入4℃冰箱30分钟3.从冰箱中取出烧杯，将血清倒入离心管，3000rpm，离心20分钟4.将上清倒入一干净量筒中，记录体积后，倒入干净烧杯中，按17.6g/100ml量取固体硫酸铵，缓慢加入上清中，边加边搅拌。4℃冰箱放置30分钟5.将烧杯中液体倒入抽滤器中，负压抽滤6.刮下滤纸上的粗提蛋白，用4ml缓冲液溶解，准备加样
二凝胶过滤层析
1.凝胶柱准备：(1)连接层析柱(2)夹住出口，加入1/3体积的0.05MpH6.4PBS，灌胶，待凝胶自然沉降约1cm时，打开出口，控制流速，60滴/分(3)层析柱填装完成后，连接下口瓶，调节流速，使入口和出口流速相同。平衡至入口pH值与出口pH值相同(即pH试纸呈色相同)，关闭出口，等待加样2.加样：用吸管吸去胶面以上的缓冲液，立即加入蛋白粗提液(沿管壁缓慢加入)3.打开出口，调流速15滴/分，待蛋白粗提液完全进入胶面，用少量缓冲液清洗管壁。连接下口瓶4.检测：用双缩脲试剂检测洗脱液。待试剂变红，开始收集，直到试剂不变色停止收集。测量并记录收集液的体积，留取1ml样品(标记为G—25样品)，放入一冷冻管中冰箱冻存;剩余的液体收集入一大试管中，作好标记，下次实验用5.洗去铵盐：全速洗脱，用奈氏试剂检测洗脱液，直到橙色消失为止，回收凝胶
【注意事项】1.盐析所用器皿一定要干燥2.盐析时，应将饱和硫酸铵或固体硫酸铵加入到血清中，且边加边搅拌3.层析柱上方要留有少量液体，避免使凝胶暴露于空气中4.凝胶过滤上样时，使样品沿管壁缓缓流下，勿冲破胶面
（信息提供：探生网生物医药）
