CLIP-tag™ Purified Protein

  • This product was discontinued on 01/01/2013
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Discontinued Products


CLIP-tag™ is a novel tool for protein research, allowing the specific, covalent attachment of virtually any molecule to a protein of interest. CLIP-tag is a small protein tag based on human O6-alkylguanine-DNA-alkyltransferase (AGT). CLIP-tag substrates are derivatives of benzylcytosine (BC). In the labeling reaction, the substituted benzyl group of the substrate is covalently attached to the reactive cysteine of CLIP-tag forming a stable thioether link. Although CLIP-tag is based on the same protein as SNAP-tag®, the benzylcytosine substrates form a separate class of substrates, different from the benzylguanine substrates recognized by SNAP-tag. CLIP-tag and SNAP-tag can be used for orthogonal simultaneous labeling.

CLIP-tag Purified Protein can be used as a positive control for in vitro labeling with various CLIP-tag fluorescent substrates. The coding sequence of CLIP-tag was cloned into a pTXB1 derived E. coli T7 expression vector. CLIP-tag protein (MW: 20,675) was expressed and purified according to the instructions in the IMPACT™ kit manual (NEB #E6901 ). The purified CLIP-tag protein was dialyzed into 1X phosphate buffered saline (PBS) solution containing 1 mM DTT at 1 mg/ml (50 μM) and stored at -80°C.

Mass spectrometry analysis indicates the CLIP-tag purified protein has two species with molecular weights of 20,675 and 20,810 (with a C-terminal DTT moiety attached).

Fluorescent in-gel detection of CLIP-tag labeled with CLIP-Vista Green. Various amounts of CLIP-tag were incubated with CLIP-Vista Green at 37°C for 60 min. The protein samples were electrophoresed on a 10–20% Tris-glycine polyacrylamide gel under denaturing conditions. The gel was imaged with Typhoon 9400 at 300V PMT with the 488/526 nm excitation/emission filter set. Lane 1, 6.25 ng; lane 2, 12.5 ng; lane 3, 25 ng; lane 4, 50 ng; lane 5, 100 ng.


  1. Storage: The CLIP-tag Purified Protein may be stored at -20°C for short term use, but should be kept at -80°C for long term storage. CLIP-tag Purified Protein is supplied at a concentration of 50 μM in 1X PBS with 1 mM DTT. Thaw and aliquot just before use.


  1. Cellular Imaging and Analysis FAQs


  1. Labeling CLIP-tag Purified Protein In Vitro (P9311)
  2. Detection by Fluorescent Imager (P9311)

Interactive Tools

Quality Control

Quality Control Assays

The following Quality Control Tests are performed on each new lot and meet the specifications designated for the product. Individual lot data can be found on the Product Summary Sheet/Datacard or Manual which can be found in the Supporting Documents section of this page. Further information regarding NEB product quality can be found here.
  • In Vitro Protein Labeling:

    The product is tested in an in vitro protein labeling reaction. After incubation the labeled product is visualized on SDS-PAGE by fluorescent detection and verified by mass spectrometry.

Safety Data Sheet

The following is a list of Safety Data Sheet (SDS) that apply to this product to help you use it safely.