Epitope tags consisting of short sequences recognized by well-characterizated antibodies have been widely used in the study of protein expression in various systems.
The HA tag (YPYDVPDYA) and Myc Tag (AEEQKLISEEDLLRKRREQLKHKLE), recognized by monoclonal antibody clones 12CA5 and 9E10, respectively, are illustrative examples. Abgent's anti-HA monoclonal antibody (Clone 12CA5) provides a simple solution to detect the expression of an HA-tagged protein in cells.
The 6xHIS tag (HHHHHH), recognized by the monoclonal antibody clone 6AT18 provides an established example of this application. 6xHIS-tagged fusion proteins are easily purified from cell lysates by affinity chromatography using Nickel-Sepharose resin. Abgent's anti-6xHIS monoclonal antibody provides a simple solution to detect the expression of HIS-tagged fusion proteins in cells.
Green fluorescent protein (GFP), originally isolated from the jellyfish Aequorea victoria, is one of the best visual reporters for monitoring gene expression in vivo and in situ. GFP is a also convenient marker for use in flow cytometry because it eliminates the need to incubate with a secondary reagent (such as dyes or antibodies) for detection. However, anti-GFP antibody is also widely used for co-immunipreciapitation, co-localization or western blotting for the confirmation of specificity when a GFP fusion protein is expressed in cells. Abgent's anti-GFP monoclonal antibody provides a simple solution to detect the expression of a GFP-tagged protein in cells. Because of its ability to spontaneously generate its own fluorophore, the green fluorescent protein (GFP) from the jellyfish Aequorea victoria is used extensively as a fluorescent marker in molecular and cell biology. The yellow fluorescent proteins (YFPs) have the longest wavelength emissions of all GFP variants examined to date. This shift in the spectrum is the result of a T203Y substitution (single-letter amino acid code), a mutation rationally designed on the basis of the X-ray structure of GFP S65T. Abgent's anti-GFP monoclonal antibody can detect both GFP and YFP but not BFP (Blue fluorescent protein) by western blotting.
The eight amino acid DYKDDDDK peptide is an established and multi-functional epitope tag and can be expressed and detected with a recombinant protein as an amino-terminal or carboxy-terminal fusion (1). Abgent's DYKDDDDK antibody binds to the same epitope recognized by Sigma's Anti-FLAG antibodies. (FLAG is a registered trademark of Sigma-Aldrich Co., which is not affiliated with Abgent).