The Evolution of SNAP-Tag Labels

The conjugation of proteins with synthetic mole-cules can be conducted in many different ways. In this Perspective, we focus on tag-based techniques and specifically on the SNAP-tag technology. The SNAP-tag technology makes use of a fusion protein between a protein of interest and an enzyme tag that enables the actual conjugation reaction. The SNAP-tag is based on the O6-alkylguanine-DNA alkyltransferase (AGT) enzyme and is optimized to react selectively with O6-benzylguanine (BG) substrates. BG-containing dye derivatives have frequently been used to introduce a fluorescent tag to a specific protein. We believe that the site-specific conjugation of polymers to proteins can significantly benefit from the SNAP-tag technology. Especially, polymers synthesized via reversible deactivation radical polymerization allow for the facile introduction of a BG end group to enable SNAP-tag conjugation.

Automated summary

Proteins can be conjugated with synthetic molecules in various ways. The SNAP-tag technology, based on a fusion protein of interest and an enzyme tag, enables the conjugation reaction. This technology uses the O6-alkylguanine-DNA alkyltransferase (AGT) enzyme to selectively react with O6-benzylguanine (BG) substrates, frequently used for introducing fluorescent tags. Utilizing the SNAP-tag technology, site-specific conjugation of polymers to proteins can be greatly improved, especially with the use of polymers synthesized via reversible deactivation radical polymerization to introduce a BG end group.