Skip to main content
. Author manuscript; available in PMC: 2014 Apr 15.
Published in final edited form as: Methods Cell Biol. 2011;102:431–461. doi: 10.1016/B978-0-12-374912-3.00017-1

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.