Phytochrome system works on exposure to light. Is there any way to control the system without using light as a control mechanism?
This actually an excellent question!
Bacteria, cyanobacteria and plants use heme as the chromophore precursor for biliverdin, (BV) phytochromobilin, and phycocyanobilin respectively. Heme, as you may well know, is a closed tetrapyrrole, while Biliverdin (as a bacterial chromphore) is an open tetrapyrrole. Thus, this "open" tetrapyrrole ring can exist in various complicated ZE & sa isomers. This creates a " HUGE CHALLENGE" to control the exact "configurational" isomeric change (example only on the C15-C16 double bond in BV in some bacterial phytochromes). Light induces this configurational isomeric change in the chromophore to start the signal transduction pathway. Light also travels in packets (photons). Thus how many photons does it take to control this specific isomeric change and how does this photon energy cause this configurational change is of intense research.
Now to get back to your question, can we use a chemical to induce this specific configurational isomeric change. Most researchers will probably say No, its too hard. I , since I like challenges, I will say Yes, although, you probably have to use a combination of a redox molecule along with some mutational changes to the protein component of the phytochrome that "locks" the chromophore ZE & sa isomers in place. The redox molecule has to release a similar amount of "packet energy" as the photons and the correct amino acid mutation is your back up to do this reverse engineering. You still will have more challenges to overcome, like how to you get the exact amount of your redox molecule into the cell and will the redox molecule cause unwanted side effects by providing unwanted energy to other parts cell metabolism?
Dear Dr. Wes Ozarowski thank you for giving interesting and highly useful inputs. I think there can be a way out.
Dear Dr. Wes Ozarowski thank you for giving interesting and highly useful inputs. I think there can be a way out.
One article on cytokinin says it has e independent or identical mechanisms of action in photomorphogenic processes. Is it possible to use Cytokinins to derive similar action in plants to that of phytochrome system?
http://priede.bf.lu.lv/grozs/AuguFiziologijas/Augu_audu_kulturas_MAG/literatura/07_Thomas%20et%20al%201997%20light%20and%20cytokinin.pdf
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