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

Area of Science:

• Biochemistry
• Biophysics
• Molecular Biology

Background:

• Fluorescence Resonance Energy Transfer (FRET) is a distance-dependent physical process where energy is transferred between two light-sensitive molecules called fluorophores.
• Red fluorescent proteins (RFPs) are valuable tools in biological research, enabling visualization and tracking of cellular processes.
• Protein oligomerization, the assembly of multiple protein subunits, is crucial for many biological functions.

Purpose of the Study:

• To investigate the mechanism of chromophore maturation in the novel red fluorescent protein wt-DsRed.
• To explore the potential of intra-oligomer FRET as a method for studying protein assembly.
• To develop an efficient screening strategy for identifying protein variants with altered oligomerization properties.

Main Methods:

• Spectroscopic analysis, including steady-state absorption and emission spectra, was used to characterize wt-DsRed.
• Ultrafast FRET measurements were employed to probe energy transfer dynamics within the protein.
• Mutagenesis of surface docking sites was performed to generate protein variants.

Main Results:

• Ultrafast FRET was observed between the immature green-emitting and mature red-emitting chromophores within wt-DsRed.
• This FRET process occurs over a short range, confirming its suitability for probing oligomerization.
• The study successfully demonstrated a method for screening protein variants with altered surface interactions.

Conclusions:

• The wt-DsRed protein exhibits an intrinsic FRET mechanism that facilitates its maturation and provides a readout for oligomerization.
• Intra-oligomer FRET is a powerful technique for studying protein assembly and screening protein variants.
• This work lays the foundation for developing novel fluorescent protein-based biosensors for protein-protein interactions.