The discovery and development of green fluorescent protein (GFP) as a tool for biomedical research was the basis for last year's Nobel Prize in Chemistry, but the protein's biological role in a cell has long been a source of debate. A research team led by Konstantin A. Lukyanov and Sergey Lukyanov at the Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, in Moscow, are now reporting that GFP may act as a light-induced electron donor, a function that suggests new applications for the protein (Nat. Chem. Biol., DOI: 10.1038/nchembio.174). The team found that GFPs isolated from a variety of creatures, including jellyfish and sea anemones, can donate two electrons to a variety of acceptors found in biological cells during photochemical reactions. This electron donation causes the light emitted by the protein to change from green to red. "It's a completely unexpected twist on the effects of proteins that everybody has been working with for more than a decade," comments Mikhail V. Matz, who studies biofluorescence at the University of Texas, Austin. The research paper's authors propose that the protein could be newly applied to monitor redox reactions or possibly serve as an oxygen radical scavenger.