Genetically encoded FRET-pair on the basis of terbium-binding peptide and red fluorescent protein

The genetically encoded FRET-pair was developed on the basis of terbium-binding peptide and red fluorescent protein DsRed2. To study fluorescence resonance energy transfer within the FRET-pair, the engineered construction was obtained, where sequences of terbium-binding peptide and red fluorescent protein DsRed2 were fused in single reading frame. The expression of this construction in strain E. coli BL21(DE3) was studied and conditions of synthesis, isolation, and purification of recombinant protein were optimized. The hydrodynamic radius of hybrid protein was determined by the method of dynamic diffusion. Energy transfer between sensitized terbium and red fluorescent protein was confirmed by the methods of fluorescence spectroscopy. The obtained FRET-pair may be used both for studies in vitro and as reporters in living cells.