Comparison List


a.k.a. CU17S-V168A

similar: mStayGold, tdStayGold

StayGold is a basic (constitutively fluorescent) green fluorescent protein published in 2022, derived from Cytaeis uchidae. It is reported to be a very rapidly-maturing dimer with low acid sensitivity.
Oligomerization Organism Molecular Weight Cofactor
Dimer Cytaeis uchidae 24.6 kDa -

FPbase ID: 71X7X


Ex λ Em λ EC (M-1 cm-1) QY Brightness pKa Maturation (min) Lifetime (ns)
496 505 159,000 0.93 147.87 4.0 14.0  

StayGold OSER Measurements

% Normal Cells OSER/NE ratio Cell Type Reference
0.502 (2967 cells) - HeLa Hirano et al. (2022)


t1/2 (s) Power Light Mode In Cell Fusion ˚C Reference
1500.0 7.4 (W/cm2) Laser Spinning Disc Confocal HeLa (fixed) TPM2 25.0 Ivorra-Molla et al. (2023)
32.0 29.0 (W/cm2) Laser Other 25.0 Ivorra-Molla et al. (2023)

StayGold Sequence

StayGold was derived from CU17S with the following mutations: V168A

GenBank: LC601652.1


Deposited: ,
Chromophore (GYG):


The high photostability and brightness of StayGold allowed us to select moderately bright cells for observation with continuous illumination and to perform experiments in which imaging performance was not limited by photobleaching.

Hirano et al. (2022)

StayGold’s head and tail are relatively short, which makes this FP sensitive to C- and N-terminal fusions. We borrowed termini from other proven FPs and found that nine amino acids from the N-terminal region of EGFP (n1 or n2) and ten amino acids at the C-terminus of dfGFP (c4) could be fused to StayGold to improve its targeting function to some subcellular components (Supplementary Fig. 9).

Hirano et al. (2022)

Our qualitative observation by wide-field (WF) microscopy suggested that, although CU17S did not fluoresce brightly in E. coli or mammalian cells, the fluorescence did not photobleach substantially. However, because it is generally assumed that there is an inverse correlation between the brightness and photostability of FPs, CU17S was not expected to improve brightness while maintaining excellent photostability. Nevertheless, through random mutagenesis of the CU17S gene, we discovered that the V168A mutation effectively improved the efficiency of both protein expression and chromophore maturation of the FP; CU17S/V168A was abundantly produced in bacteria.

Hirano et al. (2022)

Primary Reference

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