Convenient spin cup kits to purify protein interaction complexes involving either GST- or His-tagged fusion proteins.

Pierce GST Tag and His Tag Protein Interaction Pull-Down Kits contain the necessary components to capture and purify interacting proteins involving these two popular fusion protein tags. You provide the tagged fusion protein as the "bait" and the cells expressing the putative protein interaction target ("prey"), and the Pull-Down Kits provide everything else: cell lysis buffer, microcentrifuge spin columns, tag-specific affinity resin (agarose beads) and optimized buffers and protocol. The Pull-Down Kits are designed to teach the method to first-time users and to increase ease-of-use, convenience and reproducibility for experienced researchers. The procedure is conceptually simple (Figure 1).

Figure 1. Procedure summary for GST Tag and His Tag Pull-Down Kits. "Pull-down" is a small-scale affinity purification technique similar to immunoprecipitation (IP), except that the antibody function of is replaced by some other affinity system. In this case, the affinity system is either a GST-tagged protein that can be captured by glutathione agarose beads or a His-tagged protein that can be captured by metal chelate (cobalt) agarose beadst. The fusion-tagged protein acts as the "bait" to capture a putative binding partner (i.e., the "prey"). In a typical pull-down assay, the immobilized bait protein is incubated with a cell lysate. After the prescribed washing steps, the 'interactors" are selectively eluted for analysis in-gel or by Western blot.

	A.	B.
	Figure 2. SDS-PAGE analysis of GST- and His-tagged protein interaction pull-down experiments performed with the Pierce Pull-Down Kits. Gels were stained with Pierce Silver Stain (Product No. 24612). Lanes represent various control, flow-through, wash and elution fractions, as detailed in Table 1 below.

Applications:

• Discover a new protein:protein interaction from a cell lysate
• Confirm a putative interaction from a cell lysate or with a previously purified protein
• Extract protein:protein interaction information from in vitro transcription/translation lysates
  

GST Tag Protein Interaction Pull-Down Kit Highlights:

• Binds ~ 8 mg of GST-tagged fusion protein per ml of resin
• Gentle elution conditions do not denature interacting proteins
• Protocols included for use with bait and prey proteins from many different sources

His Tag Protein Interaction Pull-Down Kit Highlights:

• Binds 10-25 mg of histidine-tagged fusion protein per ml of resin
• Cobalt chelate resin is more specific for histidine-tagged fusion proteins than nickel resins, resulting in less nonspecific binding
• Protocols included for use with bait and prey proteins expressed from a variety of sample types

Related Products:
Co-Immunoprecipitation Kit
Biotinylated Protein Interaction Pull-Down Kit
Pierce Spin Cups and Columns
Cobalt Agarose Resin
Glutathione Agarose Resin

References:

1. Chai, J., Wu, J.-W., Kyin, S., Wang, X. and Shi, Y. (2000). Structural and biochemical basis of apoptotic activation by Smac/DIABLO. Nature 406, 855-862.
2. Kaelin, W.G., Jr., Pallas, D.D., DeCaprio, J.A., Kaye, F.J. and Livingston, D.M. (1991). Identification of cellular proteins that can interact specifically with the T/E1A-binding region of the retinoblastoma gene product. Cell 64, 521-532. (Discusses GST-tag pull-down assay)
3. Soutoglou, E., Katrakili, N. and Talianidis, I. (2000). Acetylation regulates transcription factor activity at multiple levels. Mol. Cell 5, 745-751. (Discusses His-tag pull-down assay)
4. Sambrook, J. and Russell, D.W. (2001). Molecular Cloning: A Laboratory Manual 3rd Edition. Chapter 18: Protein Interaction Technologies, Protocol #3: Detection of Protein-Protein Interactions using the GST Fusion Protein Pull-Down Technique. Cold Spring Harbor Laboratory Press: Plainview, NY.
5. Mori, Y. et al. (2003). J. Virol. 77(8), 4992-4999.
6. Mori, Y. et al. (2004). J. Virol. 78(9), 4609-4616.