Dutton's Lab

General design of Biological Electron Transfer

Many key oxidoreductases such as dehydrogenases, hydrogenases, nitrogenases, and the many oxygen enzymes of synthesis, drug detoxification, respiration photosynthesis, include a chain of single electron transferring redox cofactors. Porphyrins, chlorins, iron sulfur clusters, flavins or quinones are common members of the chains. The chains, which can comprise 2 to 8 cofactors, serve to ferry single electrons between one site of substrate oxidation/reduction and another, or to a place close to the surface of the enzyme where they are exchanged with other single electron transferring redox protein partners, such as cytochrome c or flavodoxin, that may diffuse between several redox enzymes in the cell. The distance covered by these often linear chains can be as long as 80 angtroms. In some energy converting membrane oxidoreductase complexes the chain is directed across 30 angtroms profile of the supporting membrane, and hence electron transfer is harnessed to the generation of transmembrane electric potentials essential to the energetic economy of the cell.