Tobacco etch virus NIa protease recognition site (TEV site)
Seven-residue junction, ENLYFQG, cleaved by the tobacco etch virus NIa protease between the glutamine and the final residue. Placed between a tag and its cargo so the tag can be removed after purification, leaving a single glycine on the released protein.
Origin: Tobacco etch virus NIa protease recognition site
Characteristics
Encodes ENLYFQG. TEV protease cuts between the glutamine at position 6 and the residue at position 7, so the released cargo keeps one residue of the site at its N terminus. The P1' position tolerates substitution: glycine and serine are both used, giving ENLYFQG and ENLYFQS. Cleavage is sequence-specific rather than structural, so the site works in most contexts where it is solvent-accessible.
Applications: Removable junction between an affinity or solubility tag and the protein of interest, cleaved after capture so the tag does not have to stay on the final product. Used in the same position as a self-cleaving 2A peptide but cut by an added enzyme rather than during translation.
Limitations: Requires adding purified TEV protease as a separate step, unlike a self-cleaving 2A peptide. Cleavage leaves one residue of the site on the released protein, so the product is not the native sequence. A site buried in a folded region may cut slowly or not at all.