Spot-Trap® Magnetic Agarose is an affinity reagent for immunoprecipitation (IP) of Spot-tagged proteins.
It consists of an anti-Spot-Tag® VHH/ Nanobody that is coupled to magnetic agarose beads.
More information about the Spot capture and detection tag here.
Spot-Tag sequence PDRVRAVSHWSS.
ChIP/ RIP analysis
On-bead enzyme assays
For protein purification use Spot-Cap
When use Spot-Trap? When use Spot-Cap? Click here.
|Product Spot-Trap Magnetic Agarose||Size 250 µL (10 reactions)||Code etma-10||Price $ 275||Buy +|
|Product Spot-Trap Magnetic Agarose||Size 500 µL (20 reactions)||Code etma-20||Price $ 475||Buy +|
|Product Spot-Trap Magnetic Agarose||Size 2.5 mL (100 reactions)||Code etma-100||Price $ 2050||Buy +|
|Product Spot-Trap Magnetic Agarose||Size 5 mL (200 reactions)||Code etma-200||Price Please inquire|
|Product Spot-Trap Magnetic Agarose||Size 10 mL (400 reactions)||Code etma-400||Price Please inquire|
|Product Spot-Trap Magnetic Agarose Kit||Size 500 µL (20 reactions)||Code etmak-20||Price $ 595||Buy +|
|Product Spot Peptide||Size 1 mg||Code ep-1||Price $ 85||Buy +|
|Product Binding Control Magnetic Agarose Beads||Size 500 µL (20 reactions)||Code bmab-20||Price $ 75||Buy +|
|Product Spot VHH, recombinant binding protein||Size 250 µL||Code etb-250||Price $ 455||Buy +|
Recombinant, monoclonal single domain antibody (sdAb) fragment
Dissociation constant KD of 6 nM
Wash buffer compatibility
2 M urea, 2 M NaCl, 10 mM DTT, 2 % Nonidet P40 Substitute, 1 % Triton X-100, 0.1 % SDS
Spot-Tag sequence motif PDRVRAVSHWSS
10 µL slurry bind ~ 7 µg of recombinant Spot-Tag fusion protein (30 kDa)
Coupled Nanobody/ VHH
Recombinant, monoclonal anti-Spot-Tag single domain antibody (sdAb) fragment
Bead size: ~ 40 µm
Storage buffer: 20 % EtOH
- SDS sample buffer
- 10 mM NaOH pH 12
Please consider whether elution is really needed. We recommend on-bead assays like on-bead digestion for MS analysis.
For protein purification and efficient elution with Spot peptide at +4°C we recommend Spot-Cap™ affinity resin.
Compatibility with mass spectrometry
The Spot-Trap is optimized for on-bead digestion. Complete tryptic digest results in 4-5 peptides.
Shipped at ambient temperature. Upon receipt store at 4°C. Stable for one year.
Protocol for immunoprecipitation
Should I use an N-terminal or C-terminal Spot-fusions? Can I also insert the Spot-Tag in the middle of my protein?
Both, an N- or C-terminal fusion work well.
The use of the Spot-Tag for internal protein tagging has to be tested case by case. The Spot-Tag peptide has to exist in a linear form and be accessible without steric hindrance from other parts of the protein of interest. An internal Spot-Tag is only likely to be recognized by the Spot-Tag nanobody if inserted into a sufficiently large and unstructured loop, an inherently unstructured domain or a lengthy domain linker.
How can I detect my Spot-fusion in Western blot application?
You can use ChromoTek's Spot-Label to detect your Spot-tagged fusion protein. Alternatively, you can use ChromoTek's Spot-Binding protein (Spot VHH, product code: etx-250) followed by incubation with a conventional anti-Llama or anti-His6 secondary antibody.
How long should I incubate my Spot-fusion sample with Spot-Label for Western blot and IF applications?
Optimal results are achieved through overnight incubation.
Should I use an N-terminal or C-terminal fusion tag?
Both the N-terminal or C-terminal fusion tag work well with the traps.
How can I avoid unspecific protein interactions binding to the trap?
How can I elute bound Spot-tagged protein from the Spot-Trap?
You can elute your Spot-fusion with 2xSDS-sample buffer or you can use 10 mM NaOH pH 12 (adjust pH immediately after elution). For protein purification and efficient elution with Spot peptide at +4°C we recommend Spot-Cap™ affinity resin.
How many mammalian cells are required for an immunoprecipitation reaction?
For one immunoprecipitation reaction, we recommend using ~10^6 - 10^7 mammalian cells. The yield is also dependent on the expression level of your protein of interest and the interaction partners.
How much cell extract should I use for an immunoprecipitation reaction?
For other type of cells than mammalian cells, we recommend using 0.5 - 1.0 mg of cell extract
Do I need to elute bound proteins from the beads for mass spectrometry analysis?
Do I need to elute my protein of interest from the beads for enzymatic assays?
What is the amount of trap slurry I need for one immunoprecipitation reaction?
25 µL slurry are sufficient for one pull-down reaction as the affinity of the traps is very high.
Specifications of Spot-Trap Agarose, Magnetic Agarose, and Magnetic Beads
Agarose (4% cross-linked)
Magnetic agarose (6% cross linked)
Magnetic Beads M-270
Porous; sold iron core
Spot-tagged protein size*
Small to large size
Small to large size
Small to very large size; no size limitation
Medium particle size
7 µg/ 10 µL
7 µg/ 10 µL
0.9 μg/ 10 μL
Magnetic separation & automation
May be centrifuged up to
2,500 x g
800 x g
8,000 x g
* Does depend on protein size and shape, protein multimers, complexes and interaction partners
** Determiend with a recombinant Spot-Tag fusion protein (30 kDa)
- NO contaminating heavy and light antibody chains
- Short incubation time of 30-60 minutes
- Just 4-5 peptides in mass spec.
- Recombinantly expressed without batch-to-batch variation
- Well-characterized and validated
- Ready to use
Spot-Trap Magnetic Agarose Kit
The Spot-Trap Magnetic Agarose is also available in a kit, including:
- Spot-Trap Magnetic Agarose
- Lysis* and wash buffers
*The lysis buffer provided is suitable for mammalian cells. For other cell types use another suitable lysis buffer.
Binding Control for Magnetic Agarose Beads
Only for research applications, not for diagnostic or therapeutic use!