Nobel Prize in chemistry commends finding and use of green fluorescent protein
GOOD STARTOne of this year’s Nobel winners, Roger Tsien, also won the 1968 Westinghouse Science Talent Search. He was 16. The above photo is from the March 16, 1968, Science News. Now called the Intel Science Talent Search, the competition is owned and operated by Science News publisher Society for Science & the Public (then called Science Service). Read the original printed story here. (PDF)Science News Making cells glow with a protein borrowed from jellyfish is
one of the brightest ideas in chemistry. At least that is what the Royal Swedish
Academy of Sciences
implied when it announced October 8 that the 2008 Nobel Prize in chemistry would
be awarded to three scientists who were instrumental in discovering green
fluorescent protein, commonly called GFP, and developing the protein as a powerful
tool for basic biological research.
Osamu Shimomura, Martin Chalfie and Roger Tsien will equally
share the $1.4 million prize.
GFP can absorb light at one energy and emit light at
another. The result is that the protein glows, and glows with a specific color,
when exposed to a specific wavelength of light. This function differs from that
of bioluminescent proteins, which can generate their own light.
"There's no doubt that GFP has changed the way we do
biology," says Jeff Lichtman, a
neuroscientist at Harvard
University.
"There's a wide range of things that can be done with GFP that are just
unthinkable without it." For instance, scientists can watch the movement
of proteins within a cell or track the migration of cells throughout the body.
Shimomura, of both the Marine Biological Laboratory in Woods
Hole, Mass., and of Boston University,
first discovered the barrel-shaped protein in jellyfish called Aequorea
victoria in 1962. He collected more than a million jellyfish in Friday Harbor, Wash.,
and extracted light-producing chemicals from the animals. While purifying a
protein called aequorin, which produces blue light in response to rising
calcium levels in a cell, Shimomura found another protein that absorbs the blue
light from aequorin and then gives off green light.
The discovery of a fluorescent protein astounded many
scientists, says Marc Zimmer, a computational chemist at Connecticut
College in New London. Inside GFP sits a chromophore, a
structure of rings that absorbs light and then emits light of lower energy.
Until GFP was discovered, all of the fluorescent molecules known in nature were
either not proteins or were pairs of proteins, in which each member performed
chemical surgery on the other and gave off light as a byproduct of the reaction,
he says.
So it came as a shock to find that GFP could twist and turn
on itself, attacking and rearranging its amino acids to form a five-sided ring
and giving off water and light.
“You have here a protein that has figured out how to do
surgery on its own gut,” says Tsien. “If you had asked us before GFP came along
whether a protein could do this, we would have said, ‘absolutely not.’ It would
be almost as if a protein could lift its wings and start flying through the air.
It would be almost as ludicrous.”
Since the discovery of the jellyfish protein, at least 125
different species have been found to contain individual proteins that are fluorescent,
all with a shape and a method for emitting light that is similar to GFP, Zimmer
says.
COLORS OF THE BRAINBOWView a gallery featuring the amazing images from the Brainbow project, which is built on work on a fluorescent protein that recently earned scientists the Nobel Prize in chemistry.Lichtman et al. Shimomura said during an Oct. 8 teleconference that he
didn’t expect to win the chemistry prize for his basic research on jellyfish. He
didn’t realize the practical uses of the green fluorescent protein until Chalfie’s
lab succeeded in producing the protein in another organism, and retaining the
protein’s ability to fluoresce, he said.
But the Japanese-born scientist “was the obvious choice” to
win a Nobel for his discovery of the molecule, says Zimmer. At least four other
scientists had a hand in developing the protein into a powerful research tool,
but no more than three people can share a Nobel Prize. "It must have been
very difficult to make the choice," Zimmer says.
Chalfie, of Columbia
University, first heard
about the protein in a seminar. He immediately realized that if he could put a
fluorescent protein into the cells of the transparent roundworm Caenorhabditis
elegans he could see which cells produced the light. He developed the gene that
encodes the fluorescent protein as a biological tag and showed its usefulness
by coloring six cells in the roundworm. Even before he published the results of his experiments in 1994, Chalfie
distributed the technology for introducing GFP into living cells to researchers
around the world.
Now the use of
fluorescent proteins is ubiquitous in biology. “I don’t know anyone who isn’t
using it,” Lichtman says. “The Green Revolution, as I call it, has become such
a dominant technology, I worried that it wouldn't get the prize because it
would be taken for granted."
Tsien, of the University of
California, San
Diego in La Jolla and of the
Howard Hughes Medical Institute, tweaked the structure of the jellyfish protein
and a red fluorescent protein found in corals to make them glow in a rainbow of
colors from the deepest purples to true red. That ability enables scientists to
track a number of different proteins or cells at once, allowing for a deeper
understanding of biological interactions.
In 1968, at age 16, Tsien won the top prize in the
Westinghouse Science Talent Search competition (now the Intel Science Talent
Search). His project explored the orientation of an ion in transition-metal
complexes. The competition is owned and operated by Society for Science &
the Public (then Science Service), which publishes Science News.
Lichtman uses a Crayola box of fluorescent proteins —most
developed by Tsien — to color neurons in mouse brains. He and his colleagues
can watch the neurons grow and develop and form and break connections with each
other in living animals. Such experiments only became possible with the
fluorescent proteins, he says.
“I’m just very pleased,” Lichtman says. "If I have to
have any qualm at all it is about the missing person," Douglas Prasher.
Prasher was the first to isolate the gene that encodes GFP, but he had
difficulty making it fluoresce when produced in another organism. His discovery
of the gene made Chalfie's and Tsien’s work possible. "I'm a bit sad that
he didn't get to share in this prize, but all three deserve it," Lichtman
says.
The Nobel Prize committee announced the winners at 5:45 a.m.
EST Wednesday, October 8. Laureates are informed of their selection before the
announcement of the prize, but Chalfie says he slept through the congratulatory
phone call from the Swedish academy because he had muted his phone a few days
earlier. He woke up about 25 minutes
later to a faintly ringing phone and recalled that the chemistry prize was
being awarded. “I decided to find out who the schnuck was who won it this
year,” he said during the October 8 teleconference. “I opened up my laptop and
discovered that I was the schnuck. The other two are very good scientists,” he
quipped.
SN staff writer Rachel
Ehrenberg contributed to this article.
Found in: Biology, Chemistry and Genes & Cells
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