PotM: Substrates for Fusion (Halo/Snap/Clip)-Tagged Proteins

PotM: Substrates for Fusion (Halo/Snap/Clip)-Tagged Proteins

Published on 25.01.2022

Discover our selection of substrates for Halo-, Snap-, and Clip-tagged proteins bearing different terminal groups suitable for further functionalization, e.g. biotinylation and Click chemistry.

Site-specific protein labeling is a versatile tool for studying protein function and interaction in living cells. Various peptide-based protein tags have been developed. Herein, we are focusing on HaloTag®, SNAP-Tag® and CLIP-TagTM, as well as corresponding substrates offered by Iris Biotech. Those labeling systems enable the specific, covalent attachment of in principle any molecule of choice to a protein of interest.

The HaloTag® is a 33 kDa self-labeling protein tag derived from the haloalkane dehalogenase DhaA from Rhodococcus rhodochrous. Its active site reacts in a nucleophilic attack with chloroalkane linker substrates to form an irreversible bond in the case of the mutated enzyme. The chloroalkane linker can easily be functionalized with a label of choice, e.g. fluorophore, biotin. For the wild-type enzyme, this intermediate would be hydrolyzed, leading to the regeneration of the enzyme.


Schematic illustration of the HaloTag® reaction

The SNAP-tag® is a 20 kDa self-labeling protein tag based on a modified form of the human O6-alkylguanine-DNA-alkyltransferase (hAGT), a DNA repair enzyme. A cysteine residue within the SNAP-tag® undergoes an irreversible reaction with synthetic O6-benzylguanine (BG) derivatives resulting in a covalent thioether bond. The BG moiety can easily be further functionalized with a label of choice, e.g. fluorophore, biotin, generally without affecting the reaction of the substrate with the SNAP-tag®.


Schematic illustration of the SNAP-tag® reaction

The CLIP-tagTM (20 kDa) is a modified version of the SNAP-tag, engineered to react with benzylcytosine (BC) instead of benzylguanine (BG). Thus, properties are similar. CLIP-tagTM- and SNAP-tag®-fused proteins can be labeled simultaneously in the same cells.


Schematic illustration of the CLIP-tagTM reaction

Table summarizing main properties of HaloTag®, SNAP-tag® and CLIP-tagTM.

  HaloTag SNAP-tag CLIP-tag
Origin Haloalkane dehalogenase (Rhodococcus rhodochrous) Human O6-alkylguanine-DNA-alkyltransferase Human O6-alkylguanine-DNA-alkyltransferase
Reactivity Chloroalkane derivatives O6-benzylguanine derivatives Benzylcytosine derivatives
Length 297 amino acids 182 amino acids 182 amino acids
Molecular Weight 33.6 kDa 19.4 kDa 19.4 kDa


Iris Biotech offers a Biotin- (RL-3860) as well as an ICG-functionalized (RL-3830) SNAP-tag® substrate, as well as the corresponding CLIP-tagTM suitable (RL-3840, RL-3870) derivatives. Biotinylated proteins can for example be selectively isolated based on the high affinity towards avidin representing a useful tool for purification, immobilization, and labeling. Indocyanine green (ICG) is a near-infrared fluorescence imaging dye (absorption maximum 800 nm + slight absorption in the visible range; emission maximum 810 nm) approved by the FDA.

As substrates for the HaloTag® various products are offered (see related products), e.g. suitable for further functionalization via Click Chemistry.

You could not find the derivative you are looking for? Please inquire for a Custom Synthesis!

SNAP-tag® is a registered trademark and CLIP-tagTM a trademark of New England Biolabs, Inc. HaloTag® is a registered trademark to Promega Corporation. HaloTag® Technology is proprietary to Promega Corporation.


Site-specific protein labeling with SNAP-Tags; N. B. Cole; Curr Protoc Protein Sci. 2013; 73(30): 1-30. https://doi.org/10.1002/0471140864.ps3001s73.

A general method for the covalent labeling of fusion proteins with small molecules in vivo; A. Keppler, S. Gendrezig, T. Gronemeyer, H. Pick, H. Vogel, K. Johnsson; Nat. Biotechnol. 2003; 21: 86-89. https://doi.org/10.1038/nbt765.

HaloTag: A Novel Protein Labeling Technology for Cell Imaging and Protein Analysis; g: v: Los; L. P. Encell, M. G. McDougall, D. D. Hartzell, N. Karassina, C. Zimprich, M. G. Wood, R. Learish, R. F. Ohana, M. Urh, D. Simpson, J. Mendez, K. Zimmerman, P. Otto, G. Vidugiris, J. Zhu, A. Darzins, D. H. Klaubert, R. F. Bulleit, K. V. Wood. ACS Chem. Biol. 2008; 3(6): 373-382. https://doi.org/10.1021/cb800025k.

Directed evolution of O6-alkylguanine-DNA alkyltransferase for efficient labeling of fusion proteins with small molecules in vivo; A. Juillerat, T. Gronemeyer, A. Keppler, S. Gendreizig, H. Pick, H. Vogel, K. Johnsson; Chem. Biol. 2003; 10(4): 313-317. https://doi.org/10.1016/s1074-5521(03)00068-1.

Site-specific, Covalent Labeling of Recombinant Antibody Fragments via Fusion to an Engineered Version of 6-O-Alkylguanine DNA Alkyltransferase; F. Kampmeier, M. Ribbert, T. Nachreiner, S. Dembski, F. Beaufils, A. Brecht, S. Barth; Bioconjugate Chem. 2009; 20(5): 1010-1015. https://doi.org/10.1021/bc9000257.

SNAP-Tag Technology: A Useful Tool to Determine Affinity Constants and Other Functional Parameters of Novel Antibody Fragments; J. Niesen, M. Sack, M. Seidel, R. Fendel, S. Barth, R. Fischer, C. Stein; Bioconjugate Chem. 2016; 27(8): 1931-1941. https://doi.org/10.1021/acs.bioconjchem.6b00315.

The clinical use of indocyanine green as a near-infrared fluorescent contrast agent for image-guided oncologic surgery. Boudewijn E. Schaafsma MD, J. Sven D. Mieog MD, Merlijn Hutteman MSc, Joost R. van der Vorst MD, Peter J.K. Kuppen PhD, Clemens W.G.M. Lwik PhD, John V. Frangioni MD, PhD, Cornelis J.H. van de Velde MD, PhD, Alexander L. Vahrmeijer MD PhD; Surg. Oncol. 2011; 104: 323-332. https://doi.org/10.1002/jso.21943.

Degradation kinetics of indocyanine green in aqueous solution. Vishal Saxena, Mostafa Sadoqi, Jun Shao; J. Pharm. Sci. 2003; 92: 2090-2097. https://doi.org/10.1002/jps.10470.

Stability assessment of indocyanine green within dextran-coated mesocapsules by absor- bance spectroscopy. Mohammad Abbas Yaseen; Jie Yu; Michael S. Wong; Bahman Anvari; Journal of Biomedical Optics 2007; 12(6): 064031. https://doi.org/10.1117/1.2821423.

Imaging proteins inside cells with fluorescent tags; G. Crivat, J. W. Taraska; Trends Biotechnol 2012; 30(1): 8-16. https://doi.org/10.1016/j.tibtech.2011.08.002.

Visualizing Biochemical Activities in Living Cells through Chemistry; L. Reymond, G. Lukinavicius, K. Umezawa, D. Maurel, M. A. Brun, A. Masharina, K. Bojkowska, B. Mollwitz, A. Schena, R. Griss, K. Johnsson; CHIMICA Int. J. Chem. 2011; 65(11): 868-871. https://doi.org/10.2533/chimia.2011.868.

Cell Penetration Profiling Using the Chloroalkane Penetration Assay; L. Peraro, K. L. Deprey, M. K. Moser, Z. Zou, H. L. Ball, B. Levine, J. A. Kritzer; J. Am. Chem. Soc. 2018; 140(36): 11360-11369. https://doi.org/10.1021/jacs.8b06144.

HaloTag technology: a versatile platform for biomedical applications; C. G. England, H. Luo and W. Cai; Bioconjug Chem 2015; 26: 975-86. https://doi.org/10.1021/acs.bioconjchem.5b00191

HaloTag: a novel protein labeling technology for cell imaging and protein analysis; G. V. Los, L. P. Encell, M. G. McDougall, D. D. Hartzell, N. Karassina, C. Zimprich, M. G. Wood, R. Learish, R. F. Ohana, M. Urh, D. Simpson, J. Mendez, K. Zimmerman, P. Otto, G. Vidugiris, J. Zhu, A. Darzins, D. H. Klaubert, R. F. Bulleit and K. V. Wood; ACS Chem Biol 2008; 3: 373-382. https://doi.org/10.1021/cb800025k

Self-labelling enzymes as universal tags for fluorescence microscopy, super-resolution microscopy and electron microscopy; V. Liss, B. Barlag, M. Nietschke, M. Hensel; Scientific Reports 2016; 5. https://doi.org/10.1038/srep17740.

Snap-, CLIP- and Halo-Tag Labelling of Budding Yeast Cells; F. Stagge, G. Y. Mitronova, V. N. Belov, C. A. Wurm, S. Jakobs; PLoS ONE 8(10): e78745. https://doi.org/10.1371/journal.pone.0078745.

Verwandte Produkte
    1. Structure image for Halo-PEG(2)-Suc

      Art-Nr.: RL-3180

      Startet von 200,00 €

    2. Structure image for Halo-PEG(5)-azide

      Art-Nr.: RL-3640

      Startet von auf Anfrage

    3. Structure image for Halo-DBCO

      Art-Nr.: RL-3670

      Startet von 250,00 €

    4. Structure image for Halo-PEG(2)-NH2*HCl

      Art-Nr.: RL-3680

      Startet von 300,00 €

    5. Structure image for Halo-PEG(4)-NH2*HCl

      Art-Nr.: RL-3690

      Startet von 400,00 €

    6. Structure image for Halo-PEG(2)-Azide

      Art-Nr.: RL-3700

      Startet von 300,00 €

    7. Structure image for Halo-PEG(4)-Azide

      Art-Nr.: RL-3710

      Startet von 900,00 €

    8. Structure image for ICG-SNAP

      Art-Nr.: RL-3830

      Startet von 300,00 €

    9. Structure image for ICG-CLIP

      Art-Nr.: RL-3840

      Startet von 300,00 €

    10. Structure image for Biotin-SNAP

      Art-Nr.: RL-3860

      Startet von 200,00 €

    11. Structure image for Biotin-Clip

      Art-Nr.: RL-3870

      Startet von 200,00 €