Streptavidin Bead Pulldown Assay to Determine Protein Homooligomerization   

Download PDF How to cite Favorites Q&A Share your feedback Cited by

In this protocol

Original research article

A brief version of this protocol appeared in:
The Journal of Biological Chemistry
Aug 2017


Pulldown assay is a conventional method to determine protein-protein interactions in vitro. Expressing a protein of interest with two different tags allows testing whether both versions can be captured via one of the two tags as homooligomeric complex. This protocol is based on streptavidin bead capture of a biotinylated protein and co-associated Flag-tagged protein using Streptavidin MagBeads.

Keywords: Pulldown assay, Protein-protein interactions, Streptavidin bead, Biotinylated protein, Homooligomeric complex


The amyloid precursor protein (APP) can form a homodimer through its large extracellular domain as well as its transmembrane domain, which plays an important role in biological function. The current protocol has been used in characterizing homo-dimerization of the APP transmembrane C-terminal 99 amino acid fragment (C99) (Yan et al., 2017). The basic principle of this assay is shown in Figure 1: The streptavidin-coated MagBeads can trap the biotinylated protein, which can pull down the interaction protein and detected by anti-FLAG antibody.

Figure 1. The principle of MagBeads-based pull-down assay. In this particular protocol, biotinylated Avi-tagged C99 proteins and associated C99-TEV site-rTA-Flag protein were used.

Copyright: © 2017 The Authors; exclusive licensee Bio-protocol LLC.
How to cite:  Readers should cite both the Bio-protocol article and the original research article where this protocol was used:
  1. Xu, T., Yan, Y., Harikumar, K. G., Miller, L. J., Melcher, K. and Xu, H. E. (2017). Streptavidin Bead Pulldown Assay to Determine Protein Homooligomerization. Bio-protocol 7(22): e2901. DOI: 10.21769/BioProtoc.2901.
  2. Yan, Y., Xu, T. H., Harikumar, K. G., Miller, L. J., Melcher, K. and Xu, H. E. (2017a). Dimerization of the transmembrane domain of amyloid precursor protein is determined by residues around the gamma-secretase cleavage sites. J Biol Chem, 292: 15826-15837.

Please login to post your questions/comments. Your questions will be directed to the authors of the protocol. The authors will be requested to answer your questions at their earliest convenience. Once your questions are answered, you will be informed using the email address that you register with bio-protocol.
You are highly recommended to post your data including images for the troubleshooting.

You are highly recommended to post your data (images or even videos) for the troubleshooting. For uploading videos, you may need a Google account because Bio-protocol uses YouTube to host videos.