SNAP-tag

SNAP-tag is a revolutionary self-labeling protein tag which combines specificity with covalent binding between the tag and its substrate. It is a 20kD protein tag which is easily expressed in a variety of common expression systems. A broad range of proteins has been successfully expressed as either N-or C-terminal SNAP-tag fusions.

SNAP-tag cleaves para-substituted benzyl guanines by transferring the substituted benzyl group to its active site and releasing free guanine. The resulting thioether bond is highly stable. There are no obvious limitations to the nature of the chemical compound that can be linked to SNAP-tag. The self labeling reaction is highly specific, because benzyl guanines are stable in biochemical conditions and no other protein reacts with this class of substance.

SNAP-tag can be used in a broad variety of experimental settings. Key uses include: labeling of fusion proteins inside living cells, and in extracts; covalent immobilization of proteins to surfaces without prior purification; and direct detection of SNAP-tag fusion proteins in SDS-PAGE gels.

SNAP-tag self labeling reaction

SNAP-tag self-immobilization reaction

Literature:

Selected Publications
Keppler A. et al.: "Labeling of fusion proteins with synthetic fluorophores in live cells." PNAS 101 (2004), pp. 9955-9959.
Keppler A. et al.:"Labeling of fusion proteins of O(6)-alkylguanine-DNA alkyltransferase with small molecules in vitro and in vivo." Methods 32 (2004), pp. 437-444.
Huber W. et al.:"SPR-based interaction studies with small molecular weight ligands using hAGT fusion proteins." Analytical Biochemistry 333(2) (2004), pp280-288.
Jongsma M.A., Litjens R. H.:"Self-assembling protein arrays on DNA chips by auto-labeling fusion proteins with a single DNA address", Proteomics,
2006 Apr. 5

All Publications Application Notes