Figure 4
Spectral images of the FRET donor mTurquoise2 fused to different FRET acceptors. The emission spectra of FRET pairs were recorded from single living cells. The sensitized emission component was calculated by unmixing the donor spectrum and the direct acceptor excitation. Black lines represent the FRET-pair spectra. Cyan lines represent the donor emission spectra. Grey lines represent direct acceptor excitation spectra. If orange or red fluorescent proteins show an evident green component, this is represented by a green line. Lines in color of the acceptor emission represent the unmixed sensitized emission. Thick lines show the average emission spectrum, dashed lines represent the standard deviations and thin lines show individual measurements. Based on these data the FRET efficiency was calculated (Table 3). The number of cells imaged is EGFP n = 37, Clover n = 36, mNeonGreen n = 46, SYFP2 n = 39, mOrange n = 24, mOrange2 n = 22, mKO2 n = 35, mKOκ n = 24, TagRFP-T n = 50, mRuby2 n = 66, mScarlet-I n = 47, mCherry n = 28, mKate2 n = 27.
