UNIT 19.20 Strep/FLAG Tandem Affinity Purification (SF-TAP) to Study Protein Interactions

  1. Christian Johannes Gloeckner1,
  2. Karsten Boldt1,2,
  3. Marius Ueffing1,2

Published Online: 1 AUG 2009

DOI: 10.1002/0471140864.ps1920s57

Current Protocols in Protein Science

Current Protocols in Protein Science

How to Cite

Gloeckner, C. J., Boldt, K. and Ueffing, M. 2009. Strep/FLAG Tandem Affinity Purification (SF-TAP) to Study Protein Interactions. Current Protocols in Protein Science. 57:19.20:19.20.1–19.20.19.

Author Information

  1. 1

    Helmholtz Zentrum München, Neuherberg, Germany

  2. 2

    Technical University of Munich, Munich, Germany

Publication History

  1. Published Online: 1 AUG 2009
  2. Published Print: AUG 2009


In recent years, several methods have been developed to analyze protein-protein interactions under native conditions. One of them, tandem affinity purification (TAP), combines two affinity-purification steps to allow isolation of high-purity protein complexes. This unit presents a methodological workflow based on an SF-TAP tag comprising a doublet Strep-tag II and a FLAG moiety optimized for rapid as well as efficient tandem affinity purification of native proteins and protein complexes in higher eukaryotic cells. Depending on the stringency of purification conditions, SF-TAP allows both the isolation of a single tagged-fusion protein of interest and purification of protein complexes under native conditions. Curr. Protoc. Protein Sci. 57:19.20.1-19.20.19. © 2009 by John Wiley & Sons, Inc.


  • SF-TAP;
  • tandem affinity purification;
  • protein complexes