Nature Chem. Biol. doi:10.1038/nchembio.174 (2009)

Green fluorescent protein (GFP), originally isolated from the jellyfish Aequorea victoria, has had a transformative effect on biology. However, its purpose in nature has remained unclear. Now, Konstantin Lukyanov of the Shemyakin and Ovchinnikov Institute for Bioorganic Chemistry in Moscow and his colleagues have discovered that GFP can transfer electrons to certain proteins in a process powered by light.

When in the presence of certain electron acceptors such as cytochrome c or benzoquinone in an in vitro system, the authors noticed that signals changed from green to red. They suggest that the protein is passing an electron and changing conformation. They also found that GFP seems able to find protein electron acceptors in living cells.

Rather than being passive light-absorbing, glowing molecules, GFP may serve a chemical role, one that the authors suggest should be considered in the many research applications of this workhorse protein.