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- 积分
- 1419
- 威望
- 1419
- 包包
- 1887
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FLAG-TAG! C$ X- P" @* V0 k$ n/ f
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FLAG-tag, or FLAG octapeptide, is a polypeptide protein tag that can be added to a protein using Recombinant DNA technology. It can be used for affinity chromatography, then used to separate recombinant, overexpressed protein from wild-type protein expressed by the host organism. It can also be used in the isolation of protein complexes with multiple subunits.& e5 C4 T0 t D/ G
/ a. o* Q% _; [$ kA Flag-tag can be used in many different assays that require recognition by an antibody. If there is no antibody against the studied protein, adding a FLAG-tag to this protein allows following the protein with an antibody against the Flag sequence. Examples are cellular localization studies by immunofluorescence or detection by SDS PAGE protein electrophoresis.5 z6 {) f8 z8 ^/ p
$ E4 ?9 F$ X: q0 p; K* iThe peptide sequence of the FLAG-tag is as follows: N-DYKDDDDK-C (1012 Da). It can be used in conjunction with other affinity tags for example a polyhistidine tag (His-tag), HA-tag or myc-tag. It can be fused to the C-terminus and the N-terminus of a protein. Some commercially available antibodies recognize the epitope only in certain positions, e.g. exclusively N-terminal. However, other available antibodies are position-insensitive.: @0 t+ ]6 c' g- i3 g$ ^ o
2 B& h! _% C; ^" Q4 J: T& ]The Flag tag was the first example of an epitope tag to be published[1] and, as the first, the only epitope tag to be patented[2]. Its structure has been optimized for compatibility with the proteins it is to be attached to, in that it is more hydrophilic than other common epitope tags, and therefore less likely to denature or inactivate proteins to which it is appended. In addition, it can readily be removed from proteins once they have been isolated, using the specific proteinase, enterokinase (enteropeptidase).$ z3 B6 l0 l) V/ x$ S% G- V& D& V% L
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Epitope tagging studies have become so widespread in modern molecular biology research, that every major disease has been studied with epitope tagging techniques and most laboratories worldwide use one or more epitope tags.4 J2 ~, S3 y# }1 ?; i
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* P- G" O5 n; E: g[edit] References
" X9 [% H6 U/ E U% \: {" |1. http://www-users.med.cornell.edu/~jawagne/FLAG-tag.html
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^ Hopp, T.P., et al. (1988) A short polypeptide marker sequence useful for recombinant protein identification and purification Bio/Technology Vol. 6, pp. 1204-1210. " L! q$ Y- X( b; L7 J7 R. C
^ Hopp, T.P., et al. (1987) Synthesis of protein with an identification peptide (vectors). United States Patent 4,703,004. |
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发表于 2009-7-17 10:37
发表于 2009-9-12 00:20
楼主下了好大的功夫了哦
这么辛苦 鼓励下