Tagging- en fusie-eiwitten

Researchers can label a protein of interest with a known protein sequence, also called a tag, to facilitate its purification and detection.

To tag a protein, its nucleotide sequence is first inserted into an expression vector containing a fusion tag.

The vector is then introduced into a host cell that can produce a recombinant or fusion protein.

Various types of fusion tags can be used depending on the intended downstream application.

Epitope tags can be used to study or detect proteins against which no antibodies are available. When a protein is tagged with a known epitope tag, such as the c-Myc peptide, it can be easily detected or purified using commercially available antibodies against c-Myc.

Histidine tags containing 2 to 10 histidine residues can also be fused onto a protein. Polyhistidine-tagged proteins can be purified using metal ion affinity chromatography columns containing divalent nickel or cobalt ions.

Fluorescent tags, like green fluorescent protein or GFP, emit fluorescence upon exposure to light. Therefore, a GFP-tagged protein can be visualized inside live cells using fluorescence microscopy.