by Séverine Altairac

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One of Nature's wonders is to produce light. Fireflies flutter and flicker in the night while other creatures are flashing light in the depths of the ocean. Brief and relatively intense flashes are used by some to ward off predators, catch prey or even seduce a future partner. This fascinating phenomenon is the achievement of a number of proteins amongst which GFP, otherwise known as Green Fluorescent Protein.

GFP was discovered by a Japanese scientist in the 1960s whilst carrying out research on jellyfish, in particular Aequorea victoria. Aequorea victoria haunts the North West Pacific where it flashes green light when the nearby tranquillity of sea water is perturbed. The green flashes emerge from the tips of its tentacles which turned out to be the home of GFP. When this luminescent protein was discovered, however, it raised more questions than it did give answers. As a result, it was shadowed and forgotten for the best part of thirty years.

A new interest in GFP arose when its 3D structure was solved. And not surprisingly. GFP sports an almost perfect barrel-shape. Besides the astonishing regularity, this very compact structure can protect its fluorescent core from any chemical damage.

How does GFP produce such an extraordinary property of emitting fluorescent light? On its own. And spontaneously. No other enzyme is necessary, just a little bit of oxygen. And this is what titillated the imagination of biologists who soon realised that if the GFP gene is introduced into a cell, you can then follow a cell's progress. Furthermore, not only is GFP non-toxic but its fluorescence is not dangerous for the cell. Today, researchers have even found ways of modifying GFP in such a way that it can emit other colours such as blue, yellow or a yellowy red!

Without a doubt, GFP has revolutionized the study of biological processes in cells and living beings. Scientists can follow almost any cell with regard to time, such as the development of an embryo, for example, or the progression of a tumour. So it hardly comes as a surprise to learn that GFP was the object of this year's Nobel prize in chemistry. Almost 50 years after its discovery. It's never too late...

Read also : "A green glow", "The greenest of us all" and "Bio-Art".

UniProt cross references
Green fluorescent protein, Aequorea victoria (Jellyfish): P42212
Protein Spotlight (ISSN 1424-4721) is a monthly review written by the Swiss-Prot team of the SIB Swiss Institute of Bioinformatics. Spotlight articles describe a specific protein or family of proteins on an informal tone. Follow us: Subscribe · Twitter · Facebook