Protein purification tags

Overview of tags added to protein to facilitate their purification

amino acid tags

Principle

A sequence of 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 stretch of amino acids to the ends of the protein to ensure its accessibility and not to disturb the protein folding.

His tag

6+ histidine (His) residues

recovered by affinity to nickel or cobalt column

more on the His tag in the Wikipedia

FLAG tag

N-DYKDDDDK-C and others

recovered with specific antibody

- more on FLAG-tag in the Wikipedia

- protocol for purification of His-tagged protein, Kafatos lab: Kafatos:His-tagged Protein Purification (denaturing)

- protocol for purification of His-tagged protein, Wittrup lab: Wittrup:His-Tag Proteins/Nickel Column Purification (suppliers, troubleshooting, etc.)

GST tag

fusion with the small glutathione-S-transferase (GST; 26 kDa)

recovery by affinity to substrate glutathione bound to a column, e.g. glutathione sepharose

- GST system of GE Healthcare [1]

myc tag

-

links

Wikipedia

• XX

• Protein tag
• Purification of a tagged protein

OWW

• example of a protocol for protein purification from bacteria: Protein Expression and Purification
• list but no content of purification methods from Berglund lab: Berglund:Protein Purification: Various Methods