Home New Customer? Create Account
Member Login:

EosFP and IrisFP Photoconvertible Fluorescent Protein

VS-FLP10010 - pwt-EosFP, with mitochondrial targeting signal, lyophilized DNA


Starting at: $922.00

Please Choose:

Shipping Option

Enter Quantity:


Green to Red Photoconvertible Fluorescent Protein

EosFP was isolated from the stony coral Lobophyllia hemprichii. Initially, the protein matures in a green fluorescent state with an emission maximum at 516 nm. Upon irradiation with violet-blue light the chromophore undergoes an irreversible photoconversion to a red state emitting at 581 nm. The wavelengths required for photoconversion and detection of the green and red fluorescent states can be easily separated, making EosFP an excellent choice for regional optical marking.

EosFP Features

  • Green to Red Photoconversion: UV/blue-inducible, permanent, bright and fast
  • Superb marker for tracking of cells, compartments, proteins in live cells
  • Nanoscopy marker using photoactivated localization microscopy (PALM)

EosFP Applications

Applications of EosFP are based on the principle that the marker is regionally photoconverted from green to red. Subsequently, the red fluorescent fraction can be tracked independently. Major applications of EosFP are:

1. Tracking of cells (cell fate mapping, tracking of metastases)

EosFP is used to label cells. The protein can be introduced into the cell by transfection of expression vectors or by microinjection of in vitro transcribed mRNA or purified recombinant protein. A desired cell or cell group is labeled and can be tracked by photoconversion (Figure 1).

Figure 1: Tracking of cells in an embyro of Xenopus laevis. Purified EosFP was microinjected at stage 2. After photoconversion of a single blastomer, the fate of descendent cells can be followed by the red fluorescence. (Picture modified from Wacker et al., 2007).

2. Tracking of subcellular compartments

EosFP is fused to a subcellular targeting signal. The organelle or parts thereof are labeled by photoconversion. The movement of the organelles can monitored subsequently (Figure 2).

Figure 2: Labeling of cellular compartments. td-EosFP was targeted to the mitochondria. After photoconversion of a single mitochondrion, fusion and fission events can be tracked. (Picture courtesy of Michael Davidson, modified from Wiedenmann & Nienhaus, 2006.)

3. Tracking of proteins

EosFP is fused to a protein of interest. After photoconversion, the movement of the marked fraction of the protein can be followed by red fluorescence (Figure 3). Figure 3: Labeling of nuclear proteins. EosFP was fused to Histone 2B (H2B, upper row) and the Recombination Signal Binding Protein (RBP, lower row). After local photoconversion within the nucleus, tracking of the red fluorescence (red channel) reveals different movements of the proteins. (Picture courtesy of Franz Oswald, modified from Wiedenmann et al., 2007.)

4. Fluorescence nanoscopy

EosFP is fused to a protein of interest. The subcellular localization can be determined with a resolution of ~20-30 nm using photoactivated localization microscopy (PALM) (4) (Figure 4).

Figure 4: Application of td-EosFP in fluorescence nanoscopy. td-EosFP was fused to vinculin and expressed in Gray fox lung fibroblast cells. Using Photoactivated Localization Microscopy (PALM) the localization in focal adhesions can be imaged with a resolution of ~20-30 nm. The figure shows a normal widefield image of a cell. The inset shows a PALM image of parts of a single focal adhesion indicated by the white rectangle. Arrows indicate a partial network structure. (Picture courtesy of Michael Davidson, modified from Shaner et al., 2007).

Practical Considerations


The green and the red fluorescent state of EosFP can be detected with standard filter sets (FITC / GFP filters for the green state or TRITC / DsRed for the red state). Fluorescence of the red state can be detected instantaneously after photoconversion. Green fluorescence can be monitored starting between 6.5 and 12 h after transfection / microinjection of vector / mRNA. Microinjection of purified EosFP allows immediate cell labeling by photoconversion.


Photoconversion can be achieved by irradiation with light of wavelengths between 350 and 440 nm with a maximal efficiency at ~390 nm. Therefore, standard DAPI filter sets can be used for photoconversion as well as customized filters with maximal transmission at 400-440 nm and appropriate lasers, e.g. a 405 nm laser diode. Photoconversion can usually be achieved within a few seconds, depending on the energy output of the light source. However, an increase of the energy beyond a limit set by the maximal conversion rate of EosFP might result in an unwanted bleaching of the red fluorescent state. In such cases, prolonged irradiation with lower light levels should be applied. At present, no negative effects of the photoconversion on expressing cells were reported.

Turnover of the red fluorescent state

Both the green and the red form of EosFP are highly stable at cytosolic pH values. A half-life of ~3 weeks was determined for the red form of wildtype EosFP in coral cells (3). In developing embryos of Xenopus laevis, the photoconverted stage could be tracked up to 14 days. In dividing cell cultures (HEK293), the red fluorescence could be traced be flow cytometry for up to 9 days.

Cell labeling vs. fusion proteins: Choice of EosFP variants

Two variants of EosFP are available from MoBiTec: The tetrameric wildtype protein (wt-EosFP) (9) and a pseudomonomeric variant in which two copies of an engineered EosFP variant are fused to form a tandem dimer (td-EosFP) (5). Both variants express functionally in a wide range of pro- and eukaryotic cells at a temperatures of 37°C or below. For the labeling of cells or tissues, tetrameric EosFP is the construct of choice. For labeling of subcellular compartements using short oligopeptide signals attached to the marker, both EosFP and td-EosFP can be considered. Although some fusion proteins with tetrameric EosFP are possible, the pseudomonomeric variant td-EosFP is the recommended construct for protein labeling. Fusions to the N-terminus of td-EosFP usually work well. Fusions to the C-terminus are also possible, however, some fusion might fail with proteins requiring a strictly monomeric marker, for instance tubulin.

Figure 5: Spectra of the green and red states of EosFP at pH 7 and pH 5.5. Solid lines, absorbance; dashed lines, excitation; dotted lines, emission spectra. (A and C) Green species at pH 7 (A) and pH 5.5 (C). Excitation (emission) spectra were measured with emission (excitation) set to 520 (490) nm.
o: conversion yields scaled to the absorbance. (Inset) In vitro chromophore maturation at 27°C determined from the absorbance at 506 nm (solid line, exponential fit). (B and D) Red species at pH 7 (B) and pH 5.5 (D). Excitation (emission) spectra were measured with emission (excitation) set to 590 (560) nm. (picture courtesy from Wiedenmann et al., 2004




Excitation before/after photoconversion (nm)



Emission before/after photoconversion (nm)



Extinction coefficient before/after photoconversion




Cat. #DescriptionAmount
VS-FLP10010pwt-EosFP, with mitochondrial targeting signal, lyophilized DNA10ug
VS-FLP10020pwt-EosFP, FLAG®-tagged, lyophilized DNA10ug
VS-FLP10030ptdEosFP, Flag®-tagged, lyophilized DNA10ug
VS-FLP10040 pmEosFP (Thermostab), Flag®-tagged, lyophilized DNA10ug
VS-FLP10050pmIrisFP, Flag®-tagged, lyophilized DNA 10ug