Comparison List


mRuby2 is a basic (constitutively fluorescent) red fluorescent protein published in 2012, derived from Entacmaea quadricolor. It has moderate acid sensitivity.
Oligomerization Organism Molecular Weight Cofactor
Monomer Entacmaea quadricolor 26.5 kDa -

FPbase ID: 8MJ78


Ex λ Em λ EC (M-1 cm-1) QY Brightness pKa Maturation (min) Lifetime (ns)
559 600 113,000 0.38 42.94 5.3 150.0 2.5

mRuby2 OSER Measurements

% Normal Cells OSER/NE ratio Cell Type Reference
87.4 ± 5.8 (10000 cells) - HeLa Cranfill et al. (2016)
33.3 (60 cells) - HeLa Costantini et al. (2015)
14.0 (113 cells) - U-2 OS Bindels et al. (2016)
87.4 ± 5.8 (10000 cells) - HeLa Shaner et al. (2013)


t1/2 (s) Power Light Mode In Cell Fusion ˚C Reference
123.0   Bindels et al. (2016)

mRuby2 Sequence

mRuby2 was derived from mRuby with the following mutations: N2_S3delinsVSKGEE/L15M/I102V/A119V/A131P/*230MextDELYK
amino acid numbers relative to eqFP611. show relative to mRuby

GenBank: AFR60232
IPG: 30275455


Negligible photochromic behavior was measured for the mScarlet variants, while TagRFP-T, mRuby2, mRuby3 and mApple showed 15%, 19%, 41%, and 51% photochromic behavior, respectively. Hence, extreme care must be taken when using the latter four RFP variants as acceptors in FRET studies, since a photochromic effect is easily confused with a changed FRET state, especially if one considers that the typical FRET contrast in many sensors is in the range of only 5–20%. The photochromic behavior can also interfere with characterization of FPs, like determination of photostability (Supplementary Fig. 8) or brightness (Supplementary Fig. 5l).

Bindels et al. (2016)

Primary Reference

Additional References

  1. Two-Photon Excitation Spectra of Various Fluorescent Proteins within a Broad Excitation Range

    Leben R, Lindquist Rl, Hauser Ae, Niesner R, Rakhymzhan A

    (2022). International Journal of Molecular Sciences, 23(21) , 13407. doi: 10.3390/ijms232113407. Article

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