Green Fluorescent ProteinApplications in Biochemistry, Cell Biology and BiotechnologyThe green fluorescent protein (GFP) of Aequorea victoria is a unique in vivo receptor for monitoring dynamic processes in cells or organisms (Gerdes & Kaether 1996, p.44). This Northern Atlantic organism is highly organized in structure, with an amazing ability to generate and emit green fluorescent light from photocytes at the margin of its umbrella, making it a perfect model for cellular studies. The molecular cloning of GFP and its demonstration by Chalfie (1988) has opened up exciting new avenues of investigation in cell biology. The enormous flexibility as a non-invasive marker in living cells allows for numerous applications of GFP (Yang F. et al. 1996, p.1246) such as a reporter for gene expression, as well as a marker to study cell lineage during development. Thus, its ability to function as a protein tag allows us to localise proteins in living cells, as it tolerates N- or C- terminal fusions to a broad variety of proteins (Tsien R.S.
E. coli GFP
Green Fluorescent Protein (GFP). Produced from PDB...
Structure et spectres de la GFP1998, p.511). These applications of GFP are now found to be more superior to conventional methods in cell biology.
GFP is a 238 amino acid protein with an apparent molecular weight of about 27-30 kDa on SDS-PAGE (Gerdes & Kaether 1996, p.44). The remarkable cylindrical fold of the protein seems ideally suited for its function, where two promoters associate together to form a dimer in the crystal, making it suitable to undergo energy transfer (Yang F. et al. 1996, p.1248). Eleven anti-parallel beta strands make up the densely compact beta-barrel, where small sections of the alpha helix form internal caps on the cylinders (Prasher D.C. et al. 1992, p. 229). This irregular alpha helical segment provides a scaffold for the chromophore which is located in the geometric centre of the cylinder. The...