The pull-down assay is an in vitro method that is widely used to detect physical interactions between protein-protein or nucleic acid-protein. In addition to confirming the interaction between substances, pull-down assays can also be used to characterize interaction conditions. For example, the use of protein domain truncation for pull-down assays can help determine functional regions that play an important role in protein interactions.
The principle of the pull-down assay is to use affinity ligands to capture interacting proteins. The standard pull-down analysis requires purified proteins with recombinant affinity tags, which have the function of "bait" and are fixed on the tag-specific affinity ligands. Then another "prey" protein is incubated with the "bait" protein. After washing, the bound protein can be eluted and identified by high-throughput methods such as LC-MS.
Figure 1. Schematic representation of protein-protein pull-down assay - Creative Proteomics
In the pull-down assay, DNA/RNA probes labeled with high-affinity tags (such as biotin) are usually used. The biotinylated DNA/RNA probes are incubated with the protein in the cell lysate, the eluted protein is detected or identified by Western blot or MS. On the contrary, it is also possible to label the protein with an affinity tag, or use an antibody against the target protein to isolate the nucleic acid-protein complex, and to detect unknown nucleic acid bound to the protein by Southern blot or PCR analysis.
Figure 2. Schematic representation of RNA–protein pull-down assay (Lanzuolo, C.; Bodega, B. 2016)
To help scientists all over the world to accurately and efficiently study the interaction between protein-protein and protein-nucleic acid, Creative Proteomics has established a professional pull-down assay platform, which is composed of experienced technical teams and sophisticated instruments. We provide a variety of pull-down measurement methods and many kinds of tags, including biotin, GST, poly-His, etc. to meet customer needs. Affinity ligands used to immobilize bait include glutathione, streptavidin, and Nickel or Cobalt chelate. In addition, we will regularly upgrade and optimize the platform to ensure that we provide customers with reliable and cost-effective services.
Customers can choose different technologies and equipment according to project requirements, or contact us directly for consultation, and our expert team will provide you with customized experimental procedures.
Creative Proteomics is an international biotechnology company dedicated to the study of intermolecular interactions and other related fields. In order to provide customers with higher quality and efficient services, we have established many powerful technical platforms to support our services, such as the upgraded pull-down assay platform. Customers can complete a large number of advanced experiments and projects on our platform.