Table 1.
Comparison Between Protein Sensors and Small-Molecule Sensors
| Name | Analyte | Sensing reaction | Selectivity | Time resolution of sensing | Fluorophores | References |
|---|---|---|---|---|---|---|
| Representative protein sensors | ||||||
| roGFP1/2 | Redox potential [GSSG]/[GSH]2 | Thiol-disulfide exchange | Mediated by protein binding | 1–10 min | GFP | (39) |
| Grx1-roGFP2 | Redox potential [GSSG]/[GSH]2 | Grx thiol-disulfide exchange | Mediated by protein binding | <1 min | GFP | (60) |
| Hyper | H2O2 | OxyR-RD thiol-disulfide exchange | Mediated by protein binding | 5–10 min | cpYFP | (9) |
| Representative small-molecule sensors | ||||||
| RealThiol | GSH | Reversible Michael addition | Mediated by appropriate chemical equilibrium | ∼1 min | High quantum yield coumarin | (66) |
| QuicGSH | GSH | Reversible nucleophilic addition | Mediated by appropriate chemical equilibrium | <1 min | Rhodamine-Si-Rhodamine FRET pair | (151) |
| QG-1 | GSH | Reversible Michael addition | Mediated by appropriate chemical equilibrium | <1 min | Coumarin | (101) |
| PF1 | H2O2 | Irreversible boronate oxidative cleavage | Mediated by selective chemical reaction | ∼5 min | Fluorescein | (15) |
FRET, Förster resonance energy transfer; Grx, glutaredoxin; GSH, glutathione; GSSG, oxidized glutathione; H2O2, hydrogen peroxide; Hyper, hydrogen peroxide sensor protein; OxyR-RD, regulator domain of E. Coli OxyR gene; PF1, peroxyfluor-1; roGFP, redox-sensitive green fluorescent protein.