Table I. Spectroscopic and biochemical properties of red-shifted FPs efficient in flow cytometry.
Protein | Oligomeric state | Exmax (nm) | Emmax (nm) | ε (M−1 cm−1) | QY | Molecular brightness | PKa | τ1/2 maturation 37 °C (h) | References |
---|---|---|---|---|---|---|---|---|---|
Orange fluorescent proteins | |||||||||
E2-Orange | Tetramer | 540 | 561 | 36,500 | 0.54 | 20 | 4.5 | 1.3 | Strack et al., 2009a |
mOrange | Monomer | 548 | 562 | 71,000 | 0.69 | 49 | 6.5 | 2.5 | Shaner et al., 2004 |
mKOκ | Monomer | 551 | 563 | 105,000 | 0.61 | 64 | 4.2 | 1.8 | Tsutsui et al., 2008 |
mOrange2 | Monomer | 549 | 565 | 58,000 | 0.60 | 35 | 6.5 | 4.5 | Shaner et al., 2008 |
tdTomato | Pseudomonomer | 554 | 581 | 138,000 | 0.69 | 95 | 4.7 | 1.0 | Shaner et al., 2004 |
TagRFP | Monomer | 555 | 584 | 98,000 | 0.41 | 40 | <4.0 | 1.7 | Merzlyak et al., 2007 |
TagRFP-T | Monomer | 555 | 584 | 81,000 | 0.41 | 33 | 4.6 | 1.7 | Shaner et al., 2008 |
Red fluorescent proteins | |||||||||
DsRed-Express2 | Tetramer | 554 | 591 | 35,600 | 0.42 | 15 | – | 0.7 | Strack et al., 2008 |
mStrawberry | Monomer | 574 | 596 | 90,000 | 0.29 | 26 | <4.5 | 0.8 | Shaner et al., 2004 |
LSSmKate2 | Monomer | 460 | 605 | 26,000 | 0.17 | 4.5 | 2.7 | 2.5 | Piatkevich et al., 2010b |
mRuby | Monomer | 558 | 605 | 112,000 | 0.35 | 39 | 5 | 2.8 | Kredel et al., 2009 |
mCherry | Monomer | 587 | 610 | 72,000 | 0.22 | 16 | <4.5 | 0.25 | Shaner et al., 2004 |
mKeima | Monomer | 440 | 620 | 14,400 | 0.24 | 3 | 6.5 | 4.7 | Kogure et al., 2006 |
mRaspberry | Monomer | 598 | 625 | 79,000 | 0.15 | 12 | 5.0 | 1.0 | Wang et al., 2004 |
Far-red fluorescent proteins | |||||||||
mKate2 | Monomer | 588 | 633 | 62,500 | 0.40 | 25 | 5.4 | <0.33 | Shcherbo et al., 2009a |
Katushka2 | Dimer | 588 | 633 | 66,250 × 2 | 0.37 | 25 × 2 | 5.4 | <0.33 | Shcherbo et al., 2009a |
E2-Crimson | Tetramer | 605 | 646 | 58,500 | 0.12 | 7 | 4.5 | 0.4 | Strack et al., 2009b |
mNeptune | Monomer | 600 | 650 | 67,000 | 0.20 | 13 | 5.4 | ND | Lin et al., 2009 |
TagRFP657 | Monomer | 611 | 657 | 34,000 | 0.10 | 3.4 | 5.0 | 2.0 | Morozova et al., 2010 |
Exmax, excitation maximum; Emmax, emission maximum; ε, molar extinction coefficient; QY, quantum yield; pKa, pH value, at which protein retains half of its fluorescent intensity; τ1/2, half-time of protein maturation. Molecular brightness is determined as a product of quantum yield and molar extinction coefficient divided by 1000. ND, not determined.