Comparison List


mApple is a basic (constitutively fluorescent) red fluorescent protein published in 2008, derived from Discosoma sp.. It is reported to be a rapidly-maturing monomer with high acid sensitivity.
Oligomerization Organism Molecular Weight Cofactor
Monomer Discosoma sp. 27.0 kDa -

FPbase ID: T5UGO


Ex λ Em λ EC (M-1 cm-1) QY Brightness pKa Maturation (min) Lifetime (ns)
568 592 75,000 0.49 36.75 6.5 30.0 2.9

mApple OSER Measurements

% Normal Cells OSER/NE ratio Cell Type Reference
95.3 ± 1.7 (10000 cells) - HeLa Cranfill et al. (2016)
87.0 (103 cells) 2.2 ± 0.2 (14 cells) U-2 OS Bindels et al. (2016)


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

mApple Sequence

mApple was derived from mOrange with the following mutations: R17H/G40A/T66M/A71V/V73I/K92R/V104I/V105I/T106H/T108N/E117V/S147E/G159S/M163K/T174A/S175A/G196D/T202V
amino acid numbers relative to DsRed. show relative to mOrange

GenBank: ABC66097


Six generations of directed evolution [of mOrange] with constant photostability selection yielded the variant mApple, which, though substantially brighter than mCherry, displayed complex photoswitching behavior. This behavior was more pronounced with continuous wide-field than with laser-scanning illumination and could be largely eliminated by excitation at alternate wavelengths or by intermittent illumination. However, given our later results using the brighter TagRFP as starting material, we chose not to pursue mApple any further.

Shaner et al. (2008)

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)

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