Table 3.
FRET characteristics for several fusion constructs of the fluorescent proteins.
Fusion construct | Förster distance, R0, nm | FRET efficiency, E | Reference |
---|---|---|---|
mTagBFP-mTagGFP | 5.25 | 0.57 ± 0.03 | this paper |
EBFP2-mTagGFP | 5.13 | 0.38 ± 0.03 | this paper |
ECFP-EYFP * | 4.86 | 0.42 *** | [24, 31] |
mCyPet-mYPet ** | 4.93 **** | 0.51 *** | [32, 33] |
Förster distances were calculated under the standard assumption of the random orientation of the chromophores. FRET efficiencies were experimentally measured using the physically linked donor and acceptor proteins.
Proteins of this widely used standard FRET pair have a tendency to form a dimer. Data on monomerized versions of the proteins are not available.
Monomerized versions of CyPet and YPet proteins, which have been specifically optimized for FRET through multiple rounds of site-specific and random mutagenesis [33]. It has been recently shown though that the original CyPet and YPet proteins form hetero- and homo-dimers in solution that substantially enhanced the observed FRET efficiency [33].
Calculated from the data [32].