Phytochromes
Phytochrome is a kind of photoreceptor in plants, bacteria and fungi, which is used to detect light. They are sensitive to light in the red and far red regions of the visible spectrum.
Phytochrome controls many aspects of plant development and is widely expressed in many tissues and developmental stages. In addition to their role in nature, the photoinduced interaction between plant phytochrome and phytochrome interacting factor (PIF) was used to control gene transcription in yeast in 2002. This is the first example of using photoproteins from another organism to control biochemical pathways.
Phytochrome is one of the optogenetics switches available at Creative BioMart. We provide plenty of services and related solutions based on the PhyB/PIF3, PhyB/PIF6 and BphP1/PpsR2 switch system.
Basic Principle of the Phytochrome System
Phytochrome consists of a protein covalently linked to the chromophore of phytobilin. The protein portion contains two identical chains (A and B ). Each chain has a PAS domain, GAF domain and PHY domain. The domains of phytochrome in plants, bacteria and fungi are arranged equally, because the three N-terminal domains are always PAS, GAF and PHY domains. However, the C-terminal domain is more diverse. The PAS domain acts as a signal sensor, and the GAF domain is responsible for combining with cGMP and sensing optical signals. These subunits together form a phytochrome region to regulate the physiological changes of plants to adapt to the changes of red and far red light conditions. In plants, red light transforms phytochrome into its bioactive form, while far red light transforms protein into its bioactive form.
Parameters and Characteristics of Each Switch System
| |
PhyB/PIF3 |
PhyB/PIF6 |
BphP1/PpsR2 |
| Photoreceptor |
Phytochrome B |
Phytochrome B |
Bacterial phytochrome P1 |
| Binding partner |
Phytochrome interacting factor 3 |
Phytochrome interacting factor 6 |
PpsR2 |
| Cofactor |
Phycocyanobilin (PCB) |
PCB |
Biliverdin |
| Source organism |
Arabidopsis thaliana |
Arabidopsis thaliana |
Rhodopseudomonas palustris |
| Mode of action |
Heterodimerization |
Heterodimerization |
Heterodimerization |
| Excitation wavelength |
660 nm |
660 nm |
760 nm |
| Reversion wavelength |
740 nm |
740 nm |
640 nm (faster), dark (slower) |
| Excitation time |
Milliseconds |
Milliseconds |
Seconds |
| Reversion time |
Milliseconds |
Milliseconds |
Seconds |
PhyB/PIF3 and PhyB/PIF6 Switch System
PhyB/PIF3 and PhyB/PIF6 are two most commonly used phytochromes switch systems. The PhyB is combined with PIF6 for mammalian cell regulation while the combination of PhyB and PIF3 is used in other cell like E. coli. The switches can be used in
Mouse genome engineering
Multi color control of mammalian cell signaling pathways
Photogenetic control of heterologous metabolism in Escherichia coli
Cre / loxP system controlled by photogenetics using red light
Photogenetic control of plant gene expression
BphP1/PpsR2 Switch System
The system is based on the backlight inducible binding between Bacterial Phytochrome BphP1 and its natural partner PpsR2 from Rhodopseudomonas palustris bacteria. Available for
Design of near infrared light sensor for Escherichia coli
Gene transcription regulation and protein targeting
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