This post is about to talk about eight regular types of protein tags for your cite.
HIS
His tag is one of the most pop protein tags. His6 refers to a spinal fusion tag combined of six histidine residues that can be inserted at the C-terminus or N-terminus of the protein of matter to. When a tag is used, one is able to be an determinant that facilitates refinement and signal detection; the other is to constitute a unusual morphological boast(binding ligand) that facilitates refinement. The side of histidine remainder has warm attractor with solid nickel, which can be used for immobilized metal chelate (IMAC) to separate and sublimate the recombinant protein.
Flag-tag
The FLAG-tagged protein is a deliquescent polypeptide(DYKDDDDK) encryption 8 amino group acids, and the Kozak succession constructed in the transmitter makes the spinal fusion protein with FLAG more competent in eukaryotic verbal expression system of rules.
AviTag
It is a short peptide of 15 amino acids with a one biotinylated lysine site, which is altogether different from the known natural biotinylated succession and can be added to the N- and C-termini of the aim protein. After spinal fusion verbalism, it can be biotinylated by vitamin H ligase. In tell to sublimate recombinant protein, low-affinity monomeric avidin or avidin is chosen, which is used for protein isolation and purification as well as nbsp;protein fundamental interaction nbsp;study.
SNAP-Tag
SNAP-tag was obtained from human O6-methylguanine-DNA methyl transfer(O6-alkylguanine-DNA-alkyltransferase). The active voice thiol site of SNAP accepts the side chain phenyl group carried by phenylmethylguanine and releases G. The valency binding of this new thioether bond allows the target protein carried by SNAP to the tag carried by the phenylmethyl aggroup.
By admixture the pure or unpurified SNAP-Tag fusion protein with the matrix immobilized with phenylmethylguanine on the rise, the protein can specifically interact with the substratum and form covalent bonds. The spinal fusion protein is indirectly immobilized on the come up of the matrix, which can reach a more expedient and speedy contemplate of Vegan operate or nbsp;protein refining nbsp;.
GST(glutathione thioltransferase)
The GST-tagged protein itself is a transferase that plays an prodigious role in detoxification, and its indigen size is 26 kD. GST fusion verbalism systems are wide used for the expression of various fusion proteins, which can be verbalized in host cells such as E. coli and yeast. Bound fusion proteins were eluted with 10 mM low glutathione under indigen conditions. GST tags can be handily detected by enzymatic assays or immunoassays. Tags help protect recombinant proteins from debasement by animate thing proteases and improve their stableness.
GFP
GFP nbsp;(green fluorescent protein) was disclosed in Portuguese man-of-war by Hamamura et al. It fluoresces putting green when excited by get down in the blue wavelength straddle. The GFP tag can be located at the C-terminus or N-terminus of the protein, and this system has been widely used in various cell types, including bacteria, barm, and mammal cells, and the corresponding GFP-tagged antibodies have also been wide used. GFP plays an key role in the detection of protein verbalism, protein and cell fluorescence tracing, and the meditate of protein interactions and conformational changes.
Regular c-Myc
C-Myc tagged protein, a small 11-amino acid tag, is uttered as an determinant in a different protein put to recognize its corresponding antibody. C-Myc tag has been successfully used in Western-blot hybridizin, immunoprecipitation and flow cytometry to find the verbalism of recombinant proteins in aim cells.
Luciferase
It is plagiaristic from the luciferin in the being, and the green ones are firefly luciferase, renilla luciferase and guassia luciferase. These luciferases are used in unit biology studies as quot;reporter proteins quot;, a technique known as newsperson gene try or luciferase assay. Unlike green fusion protein tags, newsman constructs using luciferase can be used for quantifiable depth psychology of the aim gene. It is therefore unremarkably used to contemplate the go and rule of promoters, miRNA 3 undercoat;UTR clones, because their rule of the aim gene can be gradual, rather than simple on and off states.