Figure 1
From: A New Protein-Protein Interaction Sensor Based on Tripartite Split-GFP Association

Principle of the tripartite split-GFP complementation assay.
β-strand 10 (GFP10) and β-strand 11 (GFP11) are fused to bait (A) and prey (B) proteins, respectively and the detector fragment GFP1–9 (β-strand 1–9) is added separately. When protein interaction occurs, GFP10 and GFP11 are tethered and then spontaneously associate with GFP1–9 fragment to form a full-length GFP. If proteins A and B do not interact, GFP10 and GFP11 are not tethered and entropy is too high to allow complementation with GFP1–9.