TABLE 1.
Photophysical Properties of the Nine Red GECIs
| Class | Protein | Ca2+ | ea | ρe ± 11%b | φe ± 5% | εA,max ± 5% mM−1cm−1 (λ nm) | εN,max ± 5% mM−1cm−1 (λ nm) | σ2,e,max ± 17% GM (λ nm) | F1,max ± 13% mM−1cm−1 (λ nm) | F2,max ± 21% GM (λ nm) | F1 max. ratio ± 9% (λRmax nm)c | F2 max. ratio ± 9% (2λRmax nm)c |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| I | R-GECO1 | − | A | 0.06 | 0.15 | 89 (577) | 33 (447) | 24 (1072) | 0.8 (577) | 0.21 (1072) | 23 (516) | 38 (1032) |
| + | A | 0.82 | 0.21 | 69 (563) | 30 (451) | 31 (1056) | 12 (563) | 5 (1056) | ||||
| R-GECO1.2 | − | A | 0.033 | 0.21 | 71 (573) | 27 (443) | 21 (1072) | 0.49 (573) | 0.14 (1072) | 45 (514) | 73 (1028) | |
| + | A | 0.8 | 0.31 | 56 (558) | 26 (445) | 31 (1044) | 14 (558) | 8 (1044) | ||||
| jRGECO1a | − | A | 0.054 | 0.18 | 88 (577) | 32 (447) | 18 (1076) | 0.8 (577) | 0.17 (1076) | 23 (514) | 44 (1028) | |
| + | A | 0.86 | 0.21 | 74 (563) | 39 (443) | 31 (1056) | 13 (563) | 5 (1056) | ||||
| O-GECO1 | − | A | 0.0076 | 0.22 | 80 (557) | 30 (433) | 19 (1044) | 0.14 (557) | 0.032 (1044) | 140 (502) | 220 (1004) | |
| + | A | 0.9 | 0.23 | 59 (544) | 23 (422) | 24 (1028) | 12 (544) | 5 (1028) | ||||
| CAR-GECO1 | − | A | 0.039 | 0.17 | 92 (575) | 38 (447) | 25 (1072) | 0.59 (575) | 0.16 (1072) | 42 (516) | 62 (1032) | |
| + | A | 0.9 | 0.26 | 71 (563) | 40 (425) | 36 (1060) | 17 (563) | 8 (1060) | ||||
| II | K-GECO1 | − | A | 0.25 | 0.19 | 75 (569) | 45 (451) | 16 (1068) | 3.6 (569) | 0.8 (1068) | 11 (530) | 13 (1060) |
| + | A | 0.75 | 0.48 | 84 (566) | 34 (440) | 23 (1068) | 30 (566) | 8 (1068) | ||||
| jRCaMP1a | − | A | 0.55 | 0.29 | 78 (573) | 37 (451) | 25 (1076) | 13 (573) | 4.0 (1076) | 3.4 (518) | 4.3 (1036) | |
| + | A | 0.8 | 0.54 | 77 (572) | 24 (450) | 23 (1076) | 34 (572) | 10 (1076) | ||||
| III | REX-GECO1 | − | A | 0.43 | 0.05 | 89 (583) | 34 (449) | 24 (1076) | 2.1 (583) | 0.6 (1076) | 32 (450) | 31 (900) |
| + | N | 1 | 0.21 | 83 (577) | 33 (489) | 35 (920) | 6.9 (489) | 7 (920) | ||||
| jREX-GECO1 | − | A | 0.37 | 0.06 | 86 (579) | 32 (447) | 30 (1080) | 1.9 (579) | 0.7 (1080) | 28 (450) | 26 (900) | |
| + | N | 1 | 0.21 | 78 (570) | 34 (488) | 39 (920) | 7.0 (488) | 8 (920) |
a
Excitable form of the chromophore, anionic (A) or neutral (N).
b
Estimated relative SD.
c
The Fn maximal ratios were measured directly by taking the ratio of total fluorescence signals normalized to the known relative protein concentration between the Ca2+-free and Ca2+-saturated samples.