The principles governing the transfer of electrons within proteins are significantly less complex than previously thought. Christopher Page of the University of Pennsylvania and colleagues have discovered that an electron will always be transferred if its destination is less than 14 angstroms (14 x 10-9 m) from its starting point. Their new result is based on an analysis of the common characteristics of electron transfer in more than 10,000 molecules in the Protein Data Bank (Nature 402 47).
Electron transfer in protein results from quantum tunnelling between reduction- oxidation (redox) centres. “There’s a widely accepted idea that electrons get from one redox centre to another in a protein by travelling down a series of molecular bonds that describe a best pathway,” said Christopher Moser, one of the team. “What we’ve found is that there is nothing special about that pathway. Instead, evolution ignores the structure of the protein medium between the two points and uses only proximity to ensure that the electron transfer rates are fast enough to satisfy the needs of biology.”
