Table 1.
Optical property of acid-tolerant GFP-like proteins.
| Color | Protein | λex/em a (nm) | ε b (103 M−1 cm−1) | QY c | Bright-ness d | Oligomeric State e (In Vitro/OSER) | pKa f | Resistance to Lysosomal Enzymes | Ref. |
|---|---|---|---|---|---|---|---|---|---|
| Blue | Sirius | 355/424 | 15.0 | 0.24 | 3.6 | mono/N.D. | <3.0 | Yes g | [27] |
| mTagBFP2 | 399/454 | 50.6 (76.0) | 0.64 (0.48) | 32.4 (36.5) | mono/oligo | 2.7 (2.4) | eqFP578-derivatives. Maybe no. | [28] | |
| Cyan | mTurquoise2 | 434/474 | 30.0 (31.0) | 0.93 (0.92) | 27.9 (28.5) | mono/mono | 3.1 (3.6) | avGFP-derivatives. Maybe no. [29] h | [30] |
| mCerulean3 | 434/475 | 40.0 (29.0) | 0.80 (0.80) | 32.0 (23.2) | mono/mono | 3.2 (3.4) | [31] | ||
| mTFP1 | 462/492 | 64.0 (53.0) | 0.85 (0.85) | 54.4 (45.1) | mono/mono | 4.3 (4.3) | N.D. | [32] | |
| UV-excitable Green | mT-Sapphire | 399/511 | 44.0 (34.0) | 0.60 (0.59) | 26.4 (20.1) | mono/mono | 4.9 (4.8) | avGFP-derivatives. Basically no. | [24] |
| Green | ECGFP | 463/506 | 23.9 | 0.14 | 3.3 | mono/N.D. | <4.0 | [33] | |
| mEmerald | 487/509 | 57.5 (62.0) | 0.68 (0.75) | 39.1 (46.5) | mono/mono | 6.0 (4.6) | [34] | ||
| pH-tdGFP | 488/515 | N.D. | N.D. | N.D. | tandem-dimer | 4.8 | [35] | ||
| Yellow-Green | mVenus | 515/527 | 105.0 (127.0) | 0.64 (0.67) | 67.2 (85.1) | mono/mono | 6.0 (5.4) | [36] | |
| Gamillus | 504/519 | 83.0 | 0.90 | 74.7 | mono/mono | 3.4 | Yes | [12] | |
| mNeonGreen | 506/517 | 116.0 (113.0) | 0.80 (0.80) | 92.8 (90.4) | mono/mono | 5.7 (5.4) | Maybe no [12] | [37] | |
| Orange | mKOk | 551/563 | 105.0 | 0.61 | 64.1 | mono/N.D. | 4.2 | N.D. | [38] |
| Red | mRFP1 | 584/607 | 50.0 (55.0) | 0.25 (0.35) | 12.5 (19.3) | mono/mono | 4.5 (3.8) | DsRed-derivatives. Basically yes. [39] | [13] |
| mCherry | 587/610 | 72.0 (85.0) | 0.22 (0.30) | 15.8 (25.5) | mono/mono | <4.5 (3.8) | [14] | ||
| mCherry2 | 589/610 | 79.4 | 0.22 | 17.5 | mono/N.D. | 3.3 | [15] | ||
| mStrawberry | 574/596 | 90.0 | 0.29 | 26.1 | mono/mono | <4.5 | [14] | ||
| mScarlet | 569/594 | 100.0 | 0.70 | 70.0 | mono/mono | 5.3 | [16] | ||
| mRuby | 558/605 | 112.0 (109.0) | 0.35 (0.38) | 39.2 (41.4) | mono/mono | 4.4 (4.4) | eqFP611-derivatives. Basically yes. [39] | [18] | |
| mRuby2 | 559/600 | 113.0 (107.0) | 0.38 (0.37) | 42.9 (39.6) | mono/mono | 5.3 (4.4) | [19] | ||
| mRuby3 | 558/592 | 128.0 | 0.45 | 57.6 | mono/N.D. | 4.8 | [20] | ||
| TagRFP | 555/584 | 100.0 (130.0) | 0.48 (0.33) | 48.0 (42.9) | mono/oligo | 3.1 (3.0) | eqFP578-derivatives. Basically no. [39] | [21] | |
| TagRFP-T | 555/584 | 81.0 (106.0) | 0.41 (0.32) | 33.2 (33.9) | mono/oligo | 4.6 (4.3) | [40] | ||
| FusionRed | 580/608 | 83.0 (85.0) | 0.19 (0.30) | 15.8 (25.5) | mono/mono | 4.6 (4.2) | [23] | ||
| Blue-excitable Red | LSSmKate1 | 463/624 | 31.2 | 0.08 | 2.5 | mono/N.D. | 3.2 | [25] | |
| LSSmKate2 | 460/605 | 26.0 | 0.17 | 4.4 | mono/N.D. | 2.7 | [25] | ||
| hmKeima4.15 | 436/612 | 28.0 | 0.29 | 8.1 | mono/N.D. | 5.2 | mKeima-derivative. Maybe yes. | [41] | |
| Far Red | mPlum | 590/649 | 41.0 (80.0) | 0.10 (0.13) | 4.1 (10.4) | mono/mono | <4.5 (4.6) | DsRed-derivatives. Maybe yes. | [17] |
| mRaspberry | 598/625 | 86.0 | 0.15 | 12.9 | mono/mono | <4.5 | [17] | ||
| TagRFP657 | 611/657 | 34.0 | 0.10 | 3.4 | mono/N.D. | 3.4 | eqFP578-derivatives. Maybe no. | [22] |
a Wavelength of excitation and emission peaks; b Molar extinction coefficient; c Fluorescence quantum yield; d Product of ε and QY, divided by 1000; e Oligomeric state of FPs determined by gel-filtration chromatography (in vitro) or OSER assay with mammalian cells; f pH at which fluorescence intensity becomes its half-maximal value; g Sirius is derived from avGFP, however it kept emitting fluorescence in phagosomes in Dictyostelium discoidium; h FPs from the same origin tend to show similar resistance to proteolytic degradation in lysosomes. Values without parentheses are from original articles. Values indicated in parentheses are referred from a paper [8]. N.D. indicates “Not Determined”.