Picosecond time-resolved FRET in the fluorescent protein from Discosoma Red (wt-DsRed)

Ultrafast, intra-oligomer fluorescence resonance energy transfer (FRET) between an immature green-emitting GFP-like chromophore to the mature red-emitting chromophore is found in the novel red fluorescent protein wt-DsRed (the picture shows the steady-state absorption (solid line) and emission (dotted) spectra). Since FRET is by its very nature a short range process, it represents a highly suitable method to probe oligomerization. This work describes a method preferentially applicable to the efficient screening of protein variants with mutagenetically altered surface docking sites.