Диссертация (1173136), страница 59
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And maybe it’s because that’s necessary for that first step.Later on, the asparagine-glycine goes into a different path; it also forms a ring, but it splits outammonia and so on, and they diverge.Episode X. Now there’s one important other feature about this chemistry that I have to mention –oxygen comes in, and at some stage pulls off the hydrogens that were on the tyrosine, connectingbeta-hydrogens of the tyrosine that is connected to the rest of the chromophore. So, O 2 pulls off H2,and the product is – hydrogen peroxide. H2 + O2 does not give you water in this case: you have tobalance the number of hydrogens and oxygens. H2 + O2 gives you… H2O2!, which is hydrogenperoxide.
So, there is one molecule of a toxic, slightly toxic substance that’s generated for everymolecule of GFP. And that’s sort of required by the conservation of mass: it has been now directlyverified - and it is a potential problem that GFP is not totally safe for the organism. And making aheck of a lot of GFP could generate one mole of hydrogen peroxide per every mole of GFP youmake.
And you have to keep that in mind. Now, fortunately, most organisms that have grown up inair have some defense against a slow bit of hydrogen peroxide that’s trickling out, and we seem to beOK; but it’s something that you have to keep in mind. I should also say that in this original schemewe propose that dehydration went before oxidation, and actually, that’s not quite so clear at exactlywhich stage the oxygen comes in and makes hydrogen peroxide <…>.So, in conclusion, these are some of the people in my lab, who contributed most to it. I'mshowing you the fun that you could have with these multi-colored living inks made out of fluorescentproteins, in which some people in my lab with more artistic talent than I did actually tried to draw asunset with a green flash, as you might see it from the beach not far from our lab.
Thank you verymuch.[Tsien R. Microscopy: Fluorescent Proteins (Roger Tsien) [Электронный ресурс]. – Режим доступа:https://www.youtube.com/watch?v=qK9aYnkIr3w. (последняя дата обращения 10.09.2017 г.)]AFTER YOU WATCH289Ex.13. Sit face-to-face and answer the following questions to the video.1. Who was the first to isolate green fluorescent protein from the jellyfish Aequorea Victoria?2. What important proteins does the jellyfish Aequorea Victoria contain?3. What protein enables the jellyfish to glow?4. What protein changes the color of the jellyfish from blue to green?5. What colour did the jellyfish glow when the scientists illuminated it with the UV light?6.
What colour did the jellyfish glow when the scientists poked it?7. Who was the first to publish the article on aequorin?8. Who proposed the structure of the chromophore of GFP for the first time?9. Who was the first to publish the article on the cloning of the gene?10. What aminoacids does chromophore consist of?11. What is the mechanism of this reaction?12. Is oxygen essential for chromophore to glow? How does it react with hydrogens of tyrosine?Ex.14. Decide whether these statements are true (Т), false (F). If the sentences are false, correctthem.1.
The jellyfish glows green while the scientists illuminate it with UV lamp.2. The scientist pokes the jellyfish to stimulate a green flash. The jellyfish glows green while thescientist excites it mechanically.3. While illuminating the jellyfish with the UV lamp they can see a green fluorescent circle of littledots around the rim of the jellyfish bell.4. While stirring the jellyfish with the rod it emits a white light.5. GFP changes the color of the jellyfish from the blue of aequorin to the green of GFP.6.
Osamu Shimomura was the first to publish the paper on aquorin in 1982.7. Osamu Shimomura isolated the green fluorescent protein and proposed the structure ofchromophore of GFP for the first time.8. Chromophore contains modified serine, tyrosine, glycine and arginine.9. Without oxygen chromophore can neither become fluorescent nor absorb light.10. If you express GFP in other organisms they will generate fluorescence.11.
Fred Tsuji proved that the gene alone was self-sufficient for being expressed in other organisms.12. Scientists don't know why these jellyfish evolve their glow. The purpose of both bioluminescenceand fluorescence in jellyfish is still unknown.Ex. 15. Watch the video and match the headings A-I to each part I-X of the text. One of theheadings cannot be used. There is an example at the beginning.A Fluorescent proteins are genetically codable.IAIIB The jellyfish Aequorea Victoria is the source of two valuableIIIproteins – aequorin and the green fluorescent protein.IVVC Osamu Shimomura was the first to publish the paper on aquorinVIin 1962.
He isolated the green fluorescent protein for the first time.VIIHe proposed the structure of chromophore of GFP for the first time.VIIIIXD Nobel laureates developed the mechanism of bioluminescentXreaction: the side chain amide of glycine-67 attacks the amide bondof serine-65.E Douglas Prasher published the cloning of the gene for GFP for the first time in 1992.290F A new approach to study the jellyfish Obelia medusa.G Hydrogen peroxide is formed in the bioluminescence reaction.Oxygen reacts with β-hydrogens of the tyrosine and connects the rest of the chromophore.H The structure of chromophore is similar to that of a protein.
It consists of serine, tyrosine andglycine. Chromophore glows in the presence of oxygen.I The Nobel laureates don’t have a well-accepted explanation for several phenomena observed in thejellyfish Aequorea Victoria.J The jellyfish glows green while illuminating it with the UV lamp.K The jellyfish glows green while poking it with the rod.Ex. 16. Complete each point of the plan with detailed information.I. The major impact of fluorescent proteins on cell microscopy.to provide a relatively direct link from molecular and cell biology into colorssuper-resolution………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………II.
Functions of aequorin and green fluorescent proteinAequorin enables the jellyfish to glow when it is alarmed and when the water is disturbed.The green fluorescent protein changes the color of the jellyfish from blue to green.………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………III. Unsolved issues.The Nobel laureates can’t answer the following questions:a) Why does the jellyfish want to glow?b) Why does the jellyfish glow when the water is disturbed?c) Why does the jellyfish glow green instead of blue when it is alarmed in the water?…………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………IV.
Bioluminescence observed in the jellyfish Aequorea Victoria, while illuminating it.The jellyfish glows green while exciting it with the UV lamp.The green fluorescent protein is responsible for a green flash.……………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………V. Bioluminescence observed in the jellyfish Aequorea Victoria, while poking it.During the stirring the jellyfish emits green light.…………………………………………………………………………………………………………………………………………………………………………………………………………291………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………VI.
The discovery of aequorin and the green fluorescent protein by Osamu Shimomura in 1962.…………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………VII.
The cloning of the gene for GFP proposed by Douglas Prasher in 1992.…………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………VIII. The components of chromophore structure. The condition that is essential for chromophore toglow.…………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………IX. The mechanism of the bioluminescence reaction.…………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………X.
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