Table 1.
Spectral and biochemical properties of the currently available BphP-derived monomeric NIR FPs.
| Monomeric NIR FP | Parental BphP | Ex, nm | Em, nm | Extinction coefficient, M−1cm−1 | Quantum yield, % | Molecular brightness vs. miRFP720, %a | Photostability in mammalian cells, t1/2, s | pKa | Eff. brightness in HeLa cells vs. miRFP720, %b | Reference |
|---|---|---|---|---|---|---|---|---|---|---|
| miRFP670 | RpBphP1 | 642 | 670 | 87,400 | 14.0 | 204.7 | 490 | 4.5 | 67.9 | 16 |
| miRFP670–2 | RpBphP6 | 643 | 670 | 103,000 | 13.6 | 234.3 | 310 | 4.5 | 80.8 | This paper |
| emiRFP670*c | RpBphP1 | 642 | 670 | 87,400 | 14.0 | 204.7 | 450 | 4.5 | 117.0 | |
| miRFP680* | RpBphP2 | 661 | 680 | 94,000 | 14.5 | 228.0 | 980 | 4.5 | 156.7 | |
| miRFP682 | RpBphP2 | 663 | 682 | 91,000 | 11.2 | 170.5 | 500 | 4.5 | 101.8 | |
| miRFP702 | RpBphP6 | 673 | 702 | 88,000 | 8.1 | 119.2 | 640 | 4.5 | 40.6 | |
| miRFP703 | RpBphP1 | 674 | 703 | 90,900 | 8.6 | 130.8 | 650 | 4.5 | 49.8 | 16 |
| emiRFP703* | RpBphP1 | 674 | 703 | 90,900 | 8.6 | 130.8 | 700 | 4.5 | 77.6 | This paper |
| mIFP | BrBphP | 683 | 705 | 65,900 | 6.9 | 76.1 | 90 | 4.5 | 13.9 | 19 |
| miRFP709 | RpBphP1 | 683 | 709 | 78,400 | 5.4 | 79.8 | 500 | 4.5 | 29.0 | 16 |
| miRFP713* | RpBphP2 | 690 | 713 | 99,000 | 7.0 | 115.9 | 980 | 4.5 | 94.9 | This paper |
| SNIFP | DrBphP | 697 | 720 | 149,000 | 2.2 | 54.8 | n.a. | 4.5 | n.a. | 33 |
| miRFP720* | RpBphP2 | 702 | 720 | 98,000 | 6.1 | 100.0 | 510 | 4.5 | 100 | 26 |
aMolecular brightness is a product of extinction coefficient and fluorescence emission quantum yield
bDetermined as a mean NIR fluorescence intensity of HeLa cells 48 h after transfection with no supply of exogenous BV
cA set of five spectrally distinct monomeric NIR FPs, which is recommended for further use in imaging applications, is marked with asterisks