A Re-wired Green Fluorescent Protein: Folding and Function in a Non-sequential Non-circular GFP Permutant

摘要

The sequential order of secondary structural elements in proteins affects the folding and activity to an unknown extent. To test the dependence on sequential connectivity, secondary structural elements were reconnected by their solvent-exposed ends, permuting their sequential order, called “re-wiring.” This new protein design strategy changes the topology of the backbone without changing the core sidechain packing arrangement. While circular and non-circular permutations have been observed in protein structures that are not related by sequence homology, to date no one has attempted to rationally design and construct a protein whose sequence is non-circularly permuted while conserving three-dimensional structure. Herein we show that Green Fluorescent Protein (GFP) can be rewired, still functionally fold, and exhibit wild-type fluorescence excitation and emission spectra.