GFP, stands for green fluorescent protein, and is a green fluorescent protein obtained from the jellyfish Aequorea victoria.
The protein is composed of 238 amino acids and folds into the shape of a barrel.
It has a major excitation peak at a wavelength of 395 nanometres (blue) and a minor peak at 475 nanometres. Once excited it emits light at a wavelength of 498 nanometres (green light).
It is widely used in cell biology and can be fused with other proteins of interest to determine their sub-cellular locations or identify the partners with which they bind, for example.
Fluorescent proteins are derived from GFP and have different physical properties that enable them to fluoresce in other colours.
The Nobel prize for Chemistry was awarded to its discovers in 2008.
Drawing of living bacteria expressing fluorescent proteins derived from GFP. © AndrewHires / Licence Creative Commons