Leibly, D.J. et al. Structure 23, 1754–1768 (2015).

Leibly et al. report a series of 11 engineered variants of GFP that may find applications in protein crystallography and synthetic biology. These variants oligomerize in distinct forms upon disulfide-bond formation or upon the addition of a metal ion and are based on a version of GFP that is split into a large and a small fragment. The small GFP fragment can be incorporated into a protein of interest. GFP can then be functionally reconstituted from the small and large fragments, and oligomerization results in the formation of stable, rigid structures that may facilitate the crystallization of recalcitrant proteins; such studies are currently in progress. The authors also suggest potential applications for their GFP oligomeric forms in synthetic biology, such as utilizing them as a scaffold to couple metabolic enzymes together or for constructing protein-based materials.