《常见蛋白质标签》.docx.docx

常见蛋白质标签总结 2008-12-08 22:06 Protein tags are peptide sequences ically grafted onto a binant protein. Often these tags are removable by chemical agents or by enzymatic means, such as proteolysis or intein splicing. Tags are attached to proteins for various purposes. 一、氨基酸标签(含小肽标签) A stretch of amino acids is added to the protein and enables the recovery of the labelled protein by its unique affinity. Usually its easiest to add the tag to either end of the protein to ensure its accessibility and not to disturb the protein folding. 组氨酸标签( His tag )一般为 6 个组氨酸,用 Ni2+ ( Cu2+ )亲和层析纯化 FLAG tag : N-DYKDDDDK-C , recovered with specific antibody HA tag : an epitope derived from the Influenza protein haemagglutinin (HA ,禽流感病毒血凝素), . N-YPYDVP-C , recovery with an HA antibody MYC tag : an epitope derived from the human proto-oncoprotein MYC , . N-ILKKATAYIL-C, N-EQKLISEEDL-C , recovery with an MYC antibody SBP tag : Streptavidin Binding Peptide ,链霉亲合素结合肽, 38 amino acid tag (MDEKTTGWRGGHVVEGLAGELEQLRARLEHHPQGQREP) ,更多参考在 Sigma CBP tag :钙调蛋白结合肽( CBP; 26aa )钙调蛋白结合肽与钙调素结合是 Ca2+ 依赖的,这种结合不受标签所处的位置影响( N 端和 C 端均可),在中性 pH 条件下使用 2mM EGTA 可以很方便的将目标蛋白洗脱下来。这一系统有如下优点: 1 特异性很高,因为大肠杆菌没有可以和钙调素结合的蛋白; 2与 His 标签相比可以在强还原性条件下纯化。纤维素结合肽( CBD ): 能与纤维素介质特异性的结合, 可以在温和的条件下洗脱( 乙二醇或低盐条件), pET CBD 载体含有纤维素结合肽( CBD )的序列,可方便构建。二、蛋白质标签 Rather than adding only a few amino acids a whole protein is fused to the protein to b