Cyan Fluorescent Protein/Photoswitchable to Green Fluorescence
• Photoactivatable monomeric fluorescent protein
• Photoconversion from cyan to green fluorescent form
• High contrast: photoconversion results in a more than 2000-fold increase in the green-to-cyan fluorescence ratio
• Convenient cyan label for protein tagging and FRET applications (For FRET use PhiYellow, see link below)
• High pH stability allows labeling of acidic organelles such as endosomes and lysosomes.
• Ideal for real-time protein dynamics tracking
PS-CFP2 is an improved version of the novel photoswitchable monomeric fluorescent protein PS-CFP obtained by site-directed and random mutagenesis of the aceGFP (fluorescent mutant of colourless GFP-like protein from Aequorea coerulescens. As compared to PS-CFP, PS-CFP2 comprises S108T, M153V and T154A substitutions, which led to much faster maturation and brighter fluorescence both before and after photoswitching.
PS-CFP2 is a photoactivatable dual-color protein capable of irreversible photoconversion from cyan to green fluorescent form in response to 405 nm light irradiation. After complete photoconversion more than 2000-fold growth in the green-to-cyan fluorescence ratio is observed, making PS-CFP2 the most contrasting monomeric photoactivatable fluorescent protein. It is suitable for protein labeling, protein movement tracking and fluorescent resonance energy transfer (FRET) applications.
PS-CFP2 photoconversion in transiently transfected mammalian cells.
L929 cells were transiently transfected with a plasmid encoding PS-CFP2 and examined using a fluorescence microscope. Before photoswitching no detectable green fluorescence at FITC excitation was seen. In contrast, a high-level signal was observed in the cyan channel. Upon irradiation with 10-15 micro Joules (about 20-30 W/cm2) violet dye laser (404 nm) for a few seconds, a fluorescence increase of more than 300-fold was observed in the FITC channel.
Chudakov, D.M. et al. (2007) Tracking intracellular protein movements using photoswitchable fluorescent proteins PS-CFP2 and Dendra2. Nature Protocols 2: 2024-2032.
Chudakov, D.M. et al. (2004) Photoswitchable cyan fluorescent protein for protein tracking. Nature Biotechnology 22: 1435-1439.
Gurskaya, N.G. et al. (2003) A colourless GFP homologue from the non-fluorescent hydromedusa Aequorea coerulescens and its fluorescent mutants. Biochem J. 373(Pt 2): 403-408.
Patterson, G.H. and Lippincott-Schwartz, J. A. (2002) photoactivatable GFP for selective photolabeling of proteins and cells. Science 297: 1873-1877.