Comparison List


mAmetrine is a basic (constitutively fluorescent) long stokes shift fluorescent protein published in 2008, derived from Aequorea victoria. It is reported to be a very rapidly-maturing monomer with moderate acid sensitivity.
Oligomerization Organism Molecular Weight Cofactor
Monomer Aequorea victoria 26.8 kDa -

FPbase ID: DF1S4


Ex λ Em λ EC (M-1 cm-1) QY Brightness pKa Maturation (min) Lifetime (ns)
406 526 45,000 0.58 26.1 6.0 1.8  

mAmetrine OSER Measurements

% Normal Cells OSER/NE ratio Cell Type Reference
90.0 ± 4.5 (10000 cells) - HeLa Cranfill et al. (2016)


t1/2 (s) Power Light Mode In Cell Fusion ˚C Reference
2.8   Ai et al. (2008)

mAmetrine Sequence

mAmetrine was derived from EGFP with the following mutations: S30R/Y39N/T50S/T65S/S72A/F99S/N105S/K107R/Y145M/S147V/H148W/N149D/V150A/M153T/V163A/R168E/I171V/S175G/H181A/P192S/T203F/A206K/S208F/K214Q/L231P
amino acid numbers relative to avGFP. show relative to EGFP

GenBank: ABW74903
IPG: 13918900


During the development of the violet-excitable blue-fluorescing A. victoria GFP variant mKalama1, we fortuitously discovered a long-Stokes-shift violet-excitable yellow-fluorescing variant. We subjected this new fluorescent protein to aggressive directed protein evolution and eventually produced a brightly fluorescent variant with 20 mutations relative to GFP. The final variant, designated as mAmetrine, retained the property of violet excitation owing to a protonated ground state, and yellow emission resulting from excited state proton transfer and π-π stacking interactions with the chromophore.

Ai et al. (2008)

Primary Reference

Additional References

  1. Two-photon absorption properties of fluorescent proteins

    Drobizhev M, Makarov Ns, Tillo Se, Hughes Te, Rebane A

    (2011). Nature Methods, 8(5) , 393-399. doi: 10.1038/nmeth.1596. Article   Pubmed

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