Glowing Green

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 the source of debate. Now researchers are reporting that GFP may act as a light-induced electron donor (Nat. Chem. Biol., DOI: 10.1038/nchembio.174), a function that suggests new applications for the protein.

A team of researchers led by Konstantin and Sergey Lukyanov at the Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, in Moscow, found that GFPs isolated from a variety of creatures, including jellyfish and sea anemones, could 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 researchers propose that the protein, which is already ubiquitous in laboratories, can be newly applied to monitor redox reactions or the proximity of GFP to an electron acceptor. The new functionality adds to other suggested roles for GFP, including oxygen radical scavenging and photoprotection.