常見蛋白質(zhì)標(biāo)簽總結(jié)

1、常見蛋白質(zhì)標(biāo)簽總結(jié)（Flag、HA、cMyc、CBP等）Protein tags are peptide sequences genetically grafted onto a recombinant 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、氨基酸標(biāo)簽（含小肽標(biāo)簽）A stretch o

2、f 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.1. 組氨酸標(biāo)簽（His tag）一般為6個組氨酸，用Ni2+ （Cu2+）親和層析純化2. FLAG tag ：N

3、-DYKDDDDK-C ，recovered with specific antibody3. HA tag： an epitope derived from the Influenza protein haemagglutinin (HA，禽流感病毒血凝素)，e.g. N-YPYDVPDYA-C，recovery with an HA antibody4. MYC tag： an epitope derived from the human proto-oncoprotein MYC，e.g. N-ILKKATAYIL-C, N-EQKLISEEDL-C，recovery with an M

4、YC antibody5. SBP tag：Streptavidin Binding Peptide，鏈霉親合素結(jié)合肽，38 amino acid tag (MDEKTTGWRGGHVVEGLAGELEQLRARLEHHPQGQREP)，更多參考在Sigma6. CBP tag：鈣調(diào)蛋白結(jié)合肽（CBP; 26aa）鈣調(diào)蛋白結(jié)合肽與鈣調(diào)素結(jié)合是Ca2+依賴的，這種結(jié)合不受標(biāo)簽所處的位置影響（N端和C端均可），在中性pH條件下使用2mM EGTA可以很方便的將目標(biāo)蛋白洗脫下來。這一系統(tǒng)有如下優(yōu)點：1 特異性很高，因為大腸桿菌沒有可以和鈣調(diào)素結(jié)合的蛋白；2 與His標(biāo)簽相比可以在強(qiáng)還原性條件下純化。

5、7. 纖維素結(jié)合肽（CBD）： 能與纖維素介質(zhì)特異性的結(jié)合，可以在溫和的條件下洗脫（乙二醇或低鹽條件），pET CBD 載體含有纖維素結(jié)合肽（CBD）的序列，可方便構(gòu)建。二、蛋白質(zhì)標(biāo)簽Rather than adding only a few amino acids a whole protein is fused to the protein to be purified or detected. The affinity of the attached protein enables the recovery of the artificial fusion protein. As for

6、 the peptides, the protein tag is added to either end of the target protein.1. GST tag： the small glutathione-S-transferase (GST; 26 kDa)，recovery by affinity to substrate glutathione bound to a column, e.g. glutathione sepharose2. MBP tag：麥芽糖結(jié)合蛋白（MBP; 40kDa）載體：pMAL3. IMPACT：Intein-Mediated Purifica

7、tion with an affinity Chitin-binding Tag（幾丁質(zhì)結(jié)合肽）4. 硫氧還蛋白：Thioredoxins are proteins that act as antioxidants by facilitating the reduction of other proteins by cysteine thiol-disulfide exchange.5. Protein A： a 40-60 kDa MSCRAMM surface protein originally found in the cell wall of the bacteria Staphyl

8、ococcus aureus. It has found use in biochemical research because of its ability to bind immunoglobulins. It binds proteins from many of mammalian species, most notably IgGs. It binds with the Fc region of immunoglobulins through interaction with the heavy chain. 6. Protein A/G：a recombinant fusion p

9、rotein that combines IgG binding domains of both Protein A and Protein G. Protein A/G contains four Fc binding domains from Protein A and two from Protein G, yielding a final mass of 50,460 daltons. The binding of Protein A/G is less dependent upon pH than Protein A, but otherwise has the additive p

10、roperties of Protein A and G. Protein A/G binds to all subclasses of human IgG, making it useful for purifying polyclonal or monoclonal IgG antibodies whose subclasses have not been determined. In addition, it binds to IgA, IgE, IgM and (to a lesser extent) IgD. Protein A/G also binds to all subclas

11、ses of mouse IgG but does not bind mouse IgA, IgM or serum albumin.7. GFP：綠色熒光蛋白（GFP; 26.9 kDa）GFP and its variants are the most commonly used fluorescence tags.三、化學(xué)標(biāo)簽biotin - streptavidin （生物素 - 鏈霉親合素）linking amino acids, often lysines, to cofactor and vitamin biotin purification by tight bind

12、ing to streptavidin-agarose or -beads.Streptavidin is a 53,000 dalton tetrameric protein purified from the bacterium Streptomyces avidinii. It finds wide use in molecular biology through its extraordinarily strong affinity for the vitamin biotin; the dissociation constant (Kd) of the biotin-streptavidin complex is on the order of 10-15 mol/L, ranking among one of the strongest known