Download GFP (Green fluorescent protein)

GFP
(Green fluorescent protein)
by Kitija Kaulina
GFP
(Green fluorescent protein)
• Protein GFP is
a protein that fluoresces green. This protein is
a name formed from the English names of the
first letters (Green Fluorescent Protein).
GFP
(Green fluorescent protein)
• Green Fluorescent Protein (GFP) has existed
for more than one hundred and sixty million
years in one species of jellyfish, Aequorea
victoria. The protein is found in the
photoorgans of Aequorea. GFP is not
responsible for the glow often seen in pictures
of jellyfish - that "fluorescence" is actually due
to the reflection of the flash used to
photograph the jellies.
Aequorea victoria
GFP
• The green fluorescent protein (GFP) is
a protein composed of 238 amino
acid residues (26.9 kDa) that exhibits bright
green fluorescence when exposed to blue
light. Although many other marine organisms
have similar green fluorescent proteins.
GFP
• The GFP gene can be introduced into
organisms and maintained in their genome
through breeding, injection with a viral vector,
or cell transformation. To date, the GFP gene
has been introduced and expressed in many
bacteria, yeast and other fungi, fish (such
as zebra fish), plant, fly, and mammalian cells,
including human.
GFP ribbon diagram
History of GFP
• In 1994 GFP was cloned. Now GFP is found in
laboratories all over the world where it is used in
every conceivable plant and animal. Flatworms,
algae, and pigs have all been made to fluoresce
with GFP.
• The importance of GFP was recognized in 2008
when the Nobel Committee awarded Osamu
Shimomura, Marty Chalfie and Roger Tsien
the Chemistry Nobel Prize "for the discovery and
development of the green fluorescent protein,
GFP."
Why GFP is so popular?
• GFP as the microscope of the twenty-first
century. Using GFP we can see when proteins
are made, and where they can go. This is done
by joining the GFP gene to the gene of the
protein of the interest so that when the
protein is made it will have GFP hanging off it.
Since GFP fluoresces, one can shine light at
the cell and wait for the distinctive green
fluorescence associated with GFP to appear.
GFP ready-made
• GFP is a ready-made fluorescent protein, so it
is particularly easy to use. Most proteins that
deal with light use exotic molecules to capture
and release photons. For instance, the opsins
in our eyes use retinol to sense light (see the
Molecule of the Month on
bacteriorhodopsin). These "chromophores"
must be built specifically for the task, and
carefully incorporated into the proteins.
GFP in microscope
Why GFP?
• Someone might be saying – why?who cares about this little
green protein from a jellyfish? But it turns out with
amazingly useful in scientific research, because it allows us
to look directly into the inner workings of cells. It is easy to
find out where GFP is at any given time: you just have to
shine ultraviolet light, and any GFP will glow bright green.
So here is the trick: you attach the GFP to any object that
you are interested in watching. For instance, you can attach
it to a virus. Then, as the virus spreads through the host,
you can watch the spread by following the green glow. Or,
you can attach it to a protein, and watch through the
microscope as it moves around inside cells.
GFP structure
GFP structure
• A topology diagram of the folding pattern in GFP.
The -sheet strands are shown in light green, ahelices in blue, and connecting loops in yellow.
The positions in the sequence that begin and end
each major secondary structure element are also
given. The anti-parallel strands (except for the
interactions between stands 1 and 6) make a
tightly formed barrel.
•
GFP in use
THANK YOU FOR
ATTENTION!