Far-red fluorescent protein TurboFP635

- Super bright far-red fluorescence
- Fast maturation, high photostability
- Proven suitability to generate stably transfected cell lines
- Fluorescent signal is easily distinguished from background fluorescence
- Recommended for cell and organelle labeling in autofluorescent environment, multicolor applications and whole body imaging

TurboFP635 (scientific name Katushka) is a far-red mutant of the red fluorescent protein from sea anemone Entacmaea quadricolor [Shcherbo et al., 2007]. Possessing excitation/emission maxima at 588/635 nm, TurboFP635 is 7 to 10-fold brighter compared to the spectrally close HcRed [Gurskaya et al., 2001] or mPlum [Wang et al., 2004]. TurboFP635 is characterized by fast maturation and a high pH-stability and photostability. The unique characteristics of TurboFP635 make it the protein of choice for visualization within living tissues and dual-color high-throughput assays. TurboFP635 is mainly intended for applications where fast appearance of far-red fluorescence is crucial. It is specially recommended for whole body imaging, cell and organelle labeling, and for tracking the promoter activity in auto-fluorescent tissues.

Main properties

TurboFP635 normalized excitation (thin line) and emission (thick line) spectra. Spectra viewer tool Download TurboFP635 spectra (xls)

CHARACTERISTIC * Brightness is a product of extinction coefficient and quantum yield, divided by 1000. Molecular weight, kDa 26 Polypeptide length, aa 235 Fluorescence color far-red Excitation maximum, nm 588 Emission maximum, nm 635 Quantum yield 0.34 Extinction coefficient, M-1cm-1 65 000 Brightness* 22.1 Brightness, % of EGFP 67 pKa 5.5 Structure dimer Aggregation no Maturation rate at 37°C super fast Photostability high Cell toxicity not observed Main advantages bright and fast-maturing far-red fluorescent protein; high pH-stability and photostability Possible limitations dimer, limited applicability for fusions generation

Recommended filter sets and antibodies

TurboFP635 can be recognized using Anti-tRFP antibody (Cat.# AB233-AB234) available from Evrogen.

Recommended Omega Optical filter sets are QMAX-Red and XF102-2. TurboFP635 can also be detected using Texas Red filter sets or similar.

Performance and use

TurboFP635 can be easily expressed and detected in a wide range of organisms. Mammalian cells transiently transfected with TurboFP635 expression vectors give bright fluorescent signals in 10-12 hrs after transfection. No cytotoxic effects or visible protein aggregation are observed.

		DsRed-Express and TurboFP635 expression in Xenopus laevis. Transgenic 2.5 months living animals expressing TurboFP635 and DsRed-Express under the control of cardiac actin promoter are shown from the dorsal side. TurboFP635 (on the right) is excellently visible in the whole body, while DsRed-Express (on the left) can be hardly visualized. This experiment clearly demonstrates the advantage of longer wavelength emission of TurboFP635 for the whole body imaging. Leica MZFLIII fluorescent stereomicroscope, excitation filter 546/10; emission filter 565LP. Data courtesy of Dr. A. Zaraisky, Institute of Bioorganic Chemistry, RAS (Moscow, Russia).

Despite its dimeric structure, TurboFP635 performs well in some fusions. However, for protein labeling applications we recommend using specially optimized monomeric TagFPs.

TurboFP635 suitability to generate stably transfected cells has been proven by Marinpharm company. Cell lines expressing TurboFP635 are commercially available.

TurboFP635 can be used in multicolor labeling applications with blue, cyan, green, yellow, and red (orange) fluorescent dyes.

	TurboFP635 expression in mammalian cells. (A) Transiently transfected Phoenix cells; (B) stably transfected WALKER 256 rat tumor cells; (C) stably transfected T-24 human bladder carcinoma cells; (D) stably transfected metastasizing melanoma line MelJuSo. Images of stably transfected cell lines were kindly provided by Dr. Christian Petzelt (Marinpharm).

Available variants and fusions

Variant	Description	Related vector	Cat.#
Humanized TurboFP635	TurboFP635 codon usage is optimized for high expression in mammalian cells [Haas et al., 1996], but it can be successfully expressed in many other heterological systems. Evrogen mammalian expression vectors comprising multiple cloning sites at the 5’- or 3’-end of TurboFP635 coding sequence allow easy generation of fusions of interest.	pTurboFP635-C	FP721
		pTurboFP635-N	FP722