The green glow in science, green fluorescent protein
Green fluorescent protein (GFP) was first observed in 1962 in glass jellyfish (scientific name Aequorea victoria) but it was not until 1992 that it was used for the first time in scientific research. In fact, in 2008 the Nobel Prize in Chemistry was awarded to the Japanese Osamu Shimomura who discovered GFP, and to two American Americans Martin Chalfie and Roger Y. Tsien who developed techniques to use GFP in research.
What makes a jellyfish glowing?
This protein is made up of 238 amino acids (the building blocks that make up a protein), it is small if we compare it with the most abundant protein is blood, albumin, which has 585 amino acids. The GFP fluorophore is formed by the interaction of three consecutive amino acids: serine-65, tyrosine-66, and glycine-67. It emits a 508 nm wave of green light that can be excited by blue (475 nm) and ultraviolet (UV) light (396 nm). In this way the glass jellyfish glows green under UV light.
Roger Tsien, the American biochemist, speculated that the crystal jellyfish could change the color of its bioluminescence due to the pressure change in the depths. Sadly, the jellyfish population in Friday Harbor, Washington, collapsed, making it difficult to study the animal in its natural habitat.
Green fluorescent protein: the protein which light up science
Thanks to GFP, scientists can "tag" other proteins. Let us remember that for a cell to produce proteins there is a process of interpretation of genetic information. A gene results in a protein, it is possible that the gene that produces GFP is inserted after the gene that will produce the protein we want to see. For example, having a transgenic mouse in which GFP is expressed every time they produce proteins present in the skin, what we will see is a mouse with fluorescent skin.
This was possible since the researched Martin Chalfie fantasized about integrating this protein into the DNA of his worms in order to see biological processes that were invisible. And he succeeded, he was able to follow the activity of these worms called C. elegans and provide a discovery as revolutionary as the X-rays of Marie Curie.
Although GFP seemed to be the solution to observe many phenomena, it was not a very stable fluorophore, that is, its fluorescence was lost very quickly. It was when Roger Tsien artificially developed a more stable and bright GFP and modified it to emit different colors being excited at different wavelengths, thus having the option of making combinations, so he had to give them different names such as: banana, mandarin, drink and plum.
Glowing beyond bioscience
GFP can be used to view and track proteins in living cells. When the protein is made in a cell, the fluorescent marker sticks to it. Fluorescence microscopy is used to observe, photograph, and film living cells or cellular processes without interfering with them. Viruses are normally used to infect cells and thus label them. The cloning and refinement of GFP has made it possible for scientists to examine the microscopic living world and to study all kinds of diseases such as cancer and Alzheimer's.
In addition to its great scientific application, GFP has even been used for artistic purposes, such as the case of Julian Voss-Andreae who makes sculptures of this protein. On the other hand, there are laboratories that have incorporated GFP into the genomes of animals for use as pets. Yorktown Technologies became the first company to commercialize a fluorescent zebrafish called GloFish.
Recommended link:
- https://www.youtube.com/watch?v=Z4vJ8rQCNgg
- https://www.youtube.com/watch?v=F0_q-fD_lyU
- https://www.agenciasinc.es/Noticias/Premio-Nobel-de-Quimica-2008-para-los-descubridores-de-la-proteina-fluorescente-GFP
- https://science.sciencemag.org/content/263/5148/802
ACKNOWLEDGMENTS
To Sándor Dezső for his contribution in compiling the information presented.
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