photomorphogenesis, photosensors, light signal transduction
Review seminar gfp
1. this protien has tremendous potential of applications in molecular biology i.e this is the
most extensively studied and exploited protien
2. Lukyanov and his group have found that fluorescent proteins can act as electron
donors when excited. According to their proposal published in Nature Chemical Biology
the excited green chromophore (GFP) donates an electron to an electron acceptor
forming a short lived intermediate. If no electron acceptor is available the intermediate
is permanently bleached, however if it reacts with an electron acceptor the GFP
reddens (GFP).
3. 1. He was the first person to recognise the potential of the gfp to be used as a tracer
molecule 2 he thought that GFP from a jellyfish could be used to report when a protein
was being made in a cell
4. 1. 238 aminoacids with lysine at its c terminal first aminoacid and n terminal lysine at
its end
2. Crystal structure of GFP was solved in 1996 independently by Orm¨o et al (30) and
by Yang et alAlthough GFP was first crystallized in 1974 (4) and diffraction patterns
reported
in 1988 (29), the structure was first solved in 1996 independently by
Orm¨o et al (30), Protein Data Bank accession number 1EMA, and by Yang et al
(31), accession number 1GFL. Both groups relied primarily on multiple anomalous
dispersion of selenomethionine groups to obtain phasing information from
recombinant protein. Subsequent structures of other crystal forms and mutants
(32–34a) have been solved by molecular replacement from the 1EMA
5. flourophore means that moeity of the structure which is responsible for yhe
bioluminescence in case of the gfp it is formed by the tri peptide of ser, tyr, gly
positioned from 65-67. flourescence is not an intrinsic property to this sequence this
type of sequence is present in other protiens but none is associasted with the
bioluminescence the reason being the post tranlational changes which in occurs in
them leading to the development of the flourescenceall those change are called as the
maturation of the gfp flourophore.2. it consists of ser, dehydrop tyr and gly.5 IT
involves a nucleophillic attack amide of gly67 on the carbonyl of the 65, followed by
the dehydration
6. which is followed by a much slower rate-limiting oxygenation of the Tyr66 side chain by O2 on a
timescale of hours.
finally molecular oxygen dehydrogenates the alpha –beta bond of residue 66 to put its
aromatic group in close associationn with the imidazolidone Gly67 is required for formation of
the fluorophore, no other amino acid can replace Gly in this role. The reaction is
thermosensitive. The yield of formation of the fluorophore decreases at temperatures greater
than 30 o
C
7. The most successful and numerous class of GFP applications has been as a
genetic fusion partner to host proteins to monitor their localization and fate. The
gene encoding a GFP is fused in frame with the gene encoding the endogenous
protein and the resulting chimera expressed in the cell or organism of interest.2. The
gene encoding a GFP is fused in frame with the gene encoding the endogenous
protein and the resulting chimera expressed in the cell or organism of interest.
The ideal result is a fusion protein that maintains the normal functions and
localizations of the host protein but is now fluorescent.
8. The most successful and numerous class of GFP applications has been as a
genetic fusion partner to host proteins to monitor their localization and fate. The
gene encoding a GFP is fused in frame with the gene encoding the endogenous
protein and the resulting chimera expressed in the cell or organism of interest.2. The
gene encoding a GFP is fused in frame with the gene encoding the endogenous
protein and the resulting chimera expressed in the cell or organism of interest.
The ideal result is a fusion protein that maintains the normal functions and
localizations of the host protein but is now fluorescent.
9. This was important because a small protein attached to the protein of interest was less
likely to hinder its proper function. Its small size would also allow it to follow the fused
protein, especially in oMost other bioluminescent molecules require the addition of
other substances before they glow. For example, aequorin will glow only if calcium ions
and coelenterazine have been added, and firefly luciferase requires ATP, magnesium,
and luciferin before it luminesces. This would make GFP a much more versatile tracer
than either aequorin or firefly luciferase, which were being used as tracrganelles like
neurons, whereas the diffusion of large proteins would be difficult.
10. The first proposed application of GFP was to detect gene expression in vivo
(11), especially in the nematode Caenorhabditis elegans, whose cuticle hinders
access of the substrates required for detecting other reporter genes. GFP was
particularly successful at confirming the pattern of expression of the mec-7
promoter, which drives the formation of ¯-tubulin in a limited number of
11. First genetically encoded optical sensor of membrane potential—”GFP
within Shaker potassium channel”
12. The first dynamically responsive biochemical indicators based on GFP are Ca2C
sensors, independently developed almost simultaneously by Romoser et al (109)
and by Miyawaki et al (50). Romoser et al linked commercially available class
6 BFP and class 2 GFP mutants with a 26-residue spacer containing the calmodulin
(CaM)-binding domain from avian smooth muscle myosin light chain kinase.
This spacer allowed FRET to occur from the BFP to the GFP, perhaps
because it was long and flexible enough for the two GFPs to dimerize. Addition
of Ca2C-CaM disrupted FRET, presumably by binding to and straightening the
linker so that the two GFPs were unable to dimerize
13. Brainbow is a term used to describe a process by which individual neurons
of a brain are mapped with fluorescent proteins
By controlling and varying the amount of red, green, and blue derivatives of green
fluorescent protein expressed in individual neurons, it is possible to map each neuron
with a distinctive color.
The technique was developed in the Spring of 2007 by a team led by Jeff W. Lichtman
and Joshua R. Sanes,[1]
both professors of Molecular & Cellular Biology in the
Department of Neurobiology at Harvard Medical School. While earlier techniques
allowed for mapping only a few neurons, the new method allows more than 100
differently mapped neurons can be simultaneously mapped in this manner
14. Gfp discovered from the depths of oceans is a revolutionary light which can enlighten
our understanding of cellular biology it can in future open avenues for gene expession ,
fusion tag , protien interaction , biosensors , cancer research and many more other
applications