PlasmidInfo:
PlasmidInformation
ProductName:pSF-T7-LacO-NH2-6His-Fluc-3C
ProductCode:OG4471
Size(bp):7088bp
BacterialAntibioticSelection:KanR
OriginandCompatibility:pUChighcopyderivedfrompBR322
BacterialCopyNumber:500-700percell
Promoter:
PlasmidPurpose:
ThisplasmidisdesignedtoexpresstaggedproteinsinE.coli.ItcontainstheT7promoterthatcanberegulatedusingtheLacrepressor.ThisallowsforgreatercontroloverexpressionincomparisontonormalT7promoterplasmids.InordertousethisplasmidyouwillrequireaT7polymeraseexpressingE.colicelllinethatalsoexpressestheLacIrepressor.AcommonexpressioncelllinethatcanbeusedforthispurposeistheBL21(DE3)strain.
AbouttheCleavageTag:Thisplasmidalsoencodesaproteasecleavagesitethatisdesignedtobepositionedbetweenyourgeneofinterestandthetagtoallowtheremovalofthetagfollowingproteinpurificationorisolation.Thisplasmidcontainsa3Ccleavagetag.Theproteinsequenceofthecleavagetagis:LEVLFQ?GP.HumanRhinovirus(HRV)3CProteaseisahighlyspecificproteasethatcleavesbetweentheGluandGlyresiduesofitsrecognitionsite.Itisoftenproducedwiththetrademname"PreScissionprotease".
Formoreinformationonwhichcleavagetagtouseseeourcleavagetagguide.
PromoterExpressionLevel:ThisplasmidcontainstheIPTGinducIBLepromoterthatwascreatedbythefusionoftheLacpromoterandtheTryptophanoperonpromoter.ItallowsinducibleexpressioninE.coliusingIPTGastheinducingagent.
AboutthePeptideTag:Thisplasmidcontainsann-terminalFireflyluciferasereportertagthatcanbefusedtoageneofinteresttoallowproteindetectionand/orpurification.Thesequenceofthetagis:
ThisplasmidalsocontainsasecondaryHexa-Histidine(6His)proteintag.Thesequenceofthistagis:HHHHHH
Weprovidearangeofdualpeptidetagplasmids.ThisisbecausesomepeptidetagsprovidespecificBIOLOGicalproperties(e.gsmallmoleculeaffinitynewepitopessolubilityorproteinsecretion)thatarenotprovidedbyothers.
SequenceandMap:
OtherInfo:
TranscriptionTermination:ThisplasmidcontainsthreealternativetranscriptionterminatorsforTagT7LacOInduciblebacterialandbacteriophage(T7)expression.Thismeansthatonlythepromoterneedstobechangedtoaltertheexpressionsystemyouareusing.Wesellmultiplepromotersthatcanbeusedineachofthesesystems.Thepresenceofeachterminatordoesnotreduceexpressioninthealternativesystems.
Cloning:
MakingProteinFusions:ThisplasmidhasbeendesignedtoallowthreetypesofcloningintothemainMCStojoinacodingsequencewiththetag.
CloninginaGene:Thisplasmidhasbeendesignedtobecompatiblewitharangeofcloningtechniques.Themultiplecloningsitecontainsarangeofstandardcommonlyusedrestrictionsitesforcloning.UsingthesesitesgenescanbeinsertedusingstandardcloningmethodswithDNAligase.Othermethodssuchasligaseindependentcloning(LIC)GibsonAssemblyInFusionHDorSeamlessGeneArtcanalsobeusedandbecauseallofourplasmidsarebasedonthesamebackbonethesamemethodcanbeusedforcloningintoallofourcataloguevectors.
Multiplecloningsitenotes:ThereareafewimportantsiteswithintheMCS.TheseincludetheNcoIsitetheXbaIsiteandtheBsgIandBseRIsites.TheNcoIsitecontainsastartcodonthatisimmediatelydownstreamofbothaKozakandShine-Dalgarnoribosomalbindingsite.Theseallowforoptimalpositioningofgeneswhenthestartcodonisplacedinthislocation.IfthisisnotrequiredandyouwishtouseadownstreamsiteforgenecloningyoucanremovetheNcoIsitebycleavingtheplasmidwithKpnI.
TheXbaIsitecontainsastopcodon.ThisstopcodonispositionedinaspecificpositioninrelationtotheBsgIandBseRIsitesthatareimmediatelydownstream.WheneitherBseRIorBsgIcleavetheplasmidtheyproduceaTAoverhangfromthestopcodonintheXbaIsitethatiscompatiblewithallofourpeptidetagplasmidscutwiththesamesites.BseRIandBsgIsitesarenon-palindromicandcleaveadefinednumberofbasesawayfromtheirbindingsite.
WheneverwecloneageneintoourmultiplecloningsitewealwayspositionthestartandstopcodoninthesamepositionsintheMCS.IfthestartandendsofthegenesarenotcompatiblewithNcoIandXbaIweextendthesequencetothenearestexternalsitesbutkeepthestartandstopcodonslocationsconsistent.
1:SnapFusionCloning:IfyouwouldliketofuseyourcodingsequencetothetagwithminimaladditionalbasesyoucanuseourSnapFusiontechnology.ThisprocessinvolvesamplifyingyourgenebyPCRtoaddspecificrestrictionsitesontotheends.WhenthesesitesarecuttheyproduceanoverhangthatiscompatiblewiththisplasmidcutwithBseRIorBsgI.
Toinsertyourgene:
1:Amplifyyourgenewithprimersdesignedusingthisspreadsheet
2:CuttheplasmidwitheitherBseRIorBsgI.*
3:Cutyourgenewiththeenzymeyouaddedusingthespreadsheet(anyofAcuIBpmIBpuEIBseRIBsgIEciI).
4:ClonethegeneintotheplasmidusingDNAligase.
UsingthismethodwithanN-terminaltagplasmidwillresultinthetagcodingsequenceimmediatelyfollowedbyyourgenesATGstartcodonatthejoin.Thisresultsinaseamlessfusionofthetwosequenceswithnoextrabasesbeingadded.UsingthismethodonC-terminaltagplasmidswillconvertyourgenesstopcodonintoaTAC(TyrY)codonfollowedbytheplasmidtagcodingsequence.Thisresultsinnoextrabasesbetweenyourgeneandthetag.Seethediagrambelowformoreinformation.
*PleasenotethatinsectexpressionplasmidscannotbecutwithBsgIonlyBseRIbecauseofunavoidableconflictingsitesinthebackbone.AlsoYeastplasmidscannotbecutwithBseRIbecauseofunavoidablerestrictionsitesinthebackbone.
Usingthistechniquewillcreateagenefragmentthatcanbeligatedintoanyorour>1500peptideandreportertagplasmids.Ifyouuseoneoftheothertechniquesbelow(GibsonInFusionSeamlessorLIC)youwillneednewprimersforeveryvectoryoucloneintobecausethearmsofhomologywillchangeaccordingtothetagplasmidyouarecloninginto.
Ifyoufindthatyourgenesequencehassitesinitthatmakeusingthiscloningstrategydifficultyoucanstilluseoneofthealternativemethodsbelow(e.g.standardcloningorGibsoncloning).
OpenthePrimerDesignTooltohelpyoudesignprimersforcloningyourgeneinourSnapFusiontechnique.
2:StandardEnzymes:Ifyouarenotconcernedaboutleavingafewextrabasesbetweenthetagcodingsequenceandyourgeneyoucancloneyourgeneintothevectorusingstandardcloningrestrictionenzymes.Thisstrategywillrequireyoutochoosewhichenzymesyouwanttousetocloneyourgene.
OpenthePrimerDesignToolwhichprovidesprimerswithdifferentenzymechoicespositioningyourgeneasclosetothetagaspossibleineachcase.Pleasenotethatstandardenzymeswillalwaysleaveadditionalnucleotidesbetweenyourgeneandthetagbutusingthespreadsheetwillensurethetagandgeneareinframe.
3:Gibsoncloning/InfusionHD/GeneArtSeamless/LigaseIndependentCloning(LIC)Methods:ThesecloningtechniquesusereagentssoldbyothercompaniesandallowyoutofusesequencestogetherusingenzymesthatchewbacktheDNAtoleaveoverlappingends/overhangs.ThesubsequentmethodofjoiningtheDNAdependsonthekitused.Touseoneofthesetechniquesyoucaneitherdesignyourownprimersoryoucanusethespreadsheetbelowtohelpwiththedesign.
OpenthePrimerDesignTooltohelpyoudesignprimersforcloningyourgeneusingGibsonassemblyInfusionHDGeneArtSeamlesscloningorLigaseIndependentCloning(LIC)techniques.
IPStatus:
IntellectualPropertyStatusThisproductispartofourSnapFastplasmidrange,formoreinformationontheIntellectualpropertystatusofthisplasmidpleaseclickhere
ebiomall.com






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2.加大辣根过氧化物酶标记的链霉亲和素;
我现在用商品化的试剂盒进行夹心法ELISA测定某抗体的浓度,盒子给定了4个标准品,标准品抗体浓度为70000~1000单位,测定步骤中要求对样品进行1:1000稀释后测定。
但是有的样本按照1:1000稀释后,最终OD值大于70000浓度的标准品的OD值,然后使用ELISACALC软件进行四参数拟合,超过了标准曲线的范围,就算不出来这个样品的浓度,但是如果在1000-70000之间的OD值就可以算出相应浓度。请教大神们,接下来我是否可以对样品进行1:2000,1:4000浓度稀释,算出结果后再×2、×4,算作此样品的浓度呢?还是直接给一个>70000的定性结果?或者可以有能算出来的其他软件?
Ps试剂盒中提及Dilutionlinearity(稀释线性?)为141%,这个是什么意思呢?
多谢!!
请大家帮帮忙,第一步加完抗原后必须封闭吗
目前,我用该蛋白的鼠源性单抗来包被ELISA板子,5%BSA37度封闭二小时后,洗涤四次后将板子分三个组加入抗原:其中一个组中加入的是我重组的蛋白,另一个组为用其它方法证实含该蛋白的人体内血清,最后一个组加入PBS。37度一小时后洗涤四次后每孔加入我制备的兔源性多抗。37度一小时洗涤六次后我再加入酶标记的抗兔的抗体37度40分钟后洗涤六次后TMB显色。
问题就在我显色后所有的孔都是阳性,其中以抗原为我的重组蛋白组与PBS组OD值最高,两组都可以达到1.8以上,而加入的抗原为人体血清组低,为0.6-1.0不等。
后面我优化条件,封闭液用过5%的脱脂奶粉,2%的BSA,包被的单抗浓度摸了梯度,加入的多抗也摸了梯度,酶标的抗体也摸了梯度。结果都没有改变,连趋势每次都是一样以重组蛋白组与PBS组OD最高。
今天我还试着把抗原换成其它蛋白也做出了强阳性?
请教各位高手,我的ELISA该如何往下面做了啊,是不是我的抗体本身有问题呢?
对了,我包被用的单抗是用GE公司的预装柱纯化的,很纯,在考染中是看不到一条杂带的。
ELISA双抗体夹心法(enzyme linked immunosorbent assay——sandwich technique)的原理是将特异性抗体结合到固相载体上形成固相抗体,然后和待检血清中的相应抗原结合形成免疫复合物,洗涤后再加酶标记抗体,与免疫复合物中抗原结合形成酶标抗体-抗原-固相抗体复合物,加底物显色,判断抗原含量。
生物帮有相关介绍。编码RNA http://doc.bio1000.com/show-3399.html
(2)封闭:将已包被的板用洗涤液洗涤2次,每孔加入120 μL封闭液,封闭一段时间,取出,甩干备用。
(3)竞争反应:在制备好的板中每孔加入50 μL系列浓度的标准品溶液和50 μL稀释好的酶标抗体溶液,孵育一段时间。
(4)洗板:用洗涤液洗涤5次。
(5)显色反应:每孔加入显色溶液100 μL,孵育一段时间。
(6)终止:每孔各加入终止液,在酶标仪上测定各孔的吸光值。


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