Affinity Optimized Short Peptide Tag

The Spot-Tag® has an affinity-optimized 12 amino acid sequence PDRVRAVSHWSS. The Spot-Tag is strongly bound by the Spot-Nanobody. The inert tag sequence can be added to the N-terminal and to the C-terminal side of the protein of interest. This works by PCR using modified primers or by using any of the Spot vectors offered (click here for more information). The expression of Spot-tagged proteins has been successfully tested in bacteria, yeast, mammalian cell lines, and insect cells.

Spot-Nanobody advantages
compared to other antibodies:

Spot-Tag advantages
compared to other peptide tags:

  • More robust & stable than IgG antibodies
  • High affinity of 6 nM
  • Less background than other tested affinity resins
  • Less unspecific binding than other tested capture and detection antibodies
  • Higher resolution than conventional antibodies
  • Better epitope accessibility and tissue penetration than conventional IgG antibodies
  • Less negatively charged than
    FLAG®-, Myc-, and HA-tags
  • Short
  • Inert
  • Suitable for ubiquitination assays: comprises no lysine

Overview of Spot related products by application

Immunoprecipitation (IP) & affinity purification use Spot-Trap®. Spot-Trap is the Spot-Nanobody coupled to agarose or magnetic agarose beads.

  • NO contaminating heavy & light antibody chains
  • Harsh washing conditions
  • Native & non-native elution
  • High affinity, stringent wash


Immunofluorescence (IF) & Western blotting (WB) use Spot-Label. Spot-Label is the bivalent Spot-Nanobody conjugated to fluorescent dyes. Spot-Label is the first Nanobody/ peptide-tag that was applied in super-resolution microscopy.

  • Higher resolution
  • Better epitope access & tissue penetration
  • Very small probe size


For expression of Spot-tagged fusion proteins use Spot-Tag vectors. A selection of vectors is available. Alternatively, Spot-Tag can be easily cloned by PCR primers.


For gentle & native elution of bound Spot-tagged proteins use Spot peptide.


Non-conjugated Spot-Nanobody is called Spot VHH, recombinant binding protein:

  • Very sensitive in Western blot and ELISA
  • Coupling of dyes, biotin, etc. via NHS Ester reaction

Free samples available

Request free sample here and test Spot in your experiment.