Notes On Green Fluorescent Proteins

910 WordsOct 18, 20154 Pages
1. Green Fluorescent Protein (GFP) GFP is a widely used tool in the field of Molecular biology and Cell biology. It involves emission of fluorescence under Ultra Violet light which allows for direct investigation into the inner working of cells. Green Fluorescent Protein was first isolated from the jelly fish Aequorea victoria by Osamu Shimomura (Shimomura et al., 1962). Since its discovery, it has become useful in the field of science. The GFP chromophore is formed from tri peptide in the primary structure of GFP. Its fluorescence is turned on when exposed to molecular oxygen. The gene of GFP has been introduced into many bacteria, yeast, fungi, plants and humans (Amsterdam, A. et al., 1996) and it is still gaining rapid ground in the field of biological science. 2. Structure of the Green Fluorescent Protein The GFP is composed of two structures; a barrel beta structure consisting of 11 beta strands and an alpha helix containing the covalently bonded chromophore 4-p-(hydroxybenzylidene) imidazolidin-5-one. The chromophore is in the centre of the barrel beta structure (Tsien, 1998). The size of the beta structure is 42Å long and 24Å in diameter. Due to its length and width it creates a beta like structure which is common in the GFP family (Yang, 1996). The chromophore is made from a tri-peptide Ser65–Tyr66–Gly67. To form its structure GFP first folds into a nearly native conformation, then the imidazolinoneis is formed by nucleophilic attack of the amide of Gly67 on the
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