How does green fluorescent protein (GFP)work?

Green Fluorescent Protein is composed of 238 amino acids that fold into a compact structure known as a beta-barrel. Within this structure, a chromophore is formed from three amino acids (on numbers 65-67) through a post-translational modification process. This process involves the cyclization and oxidation of a serine-tyrosine-glycine tripeptide and the dehydrogenation of tyrosine. GFP absorbs light at a wavelength of around 488 nm. This absorbed light energy causes the chromophore to enter an excited state. The excited chromophore then emits light at a longer wavelength, typically around 509 nm, which corresponds to green light. The emitted green light gives GFP its characteristic fluorescence. This property allows GFP to be easily visualized and tracked within cells.