Electron tunneling chains of mitochondria.
The single, simple concept that natural selection adjusts distances between redox cofactors goes a long way towards encompassing natural electron transfer protein design. Distances are short or long as required to direct or insulate promiscuously tunneling single electrons. Along a chain, distances are usually 14 A or less. Shorter distances are needed to allow climbing of added energetic barriers at paired-electron catalytic centers in which substrate and the required number of cofactors form a compact cluster. When there is a short-circuit danger, distances between shorting centers are relatively long. Distances much longer than 14 A will support only very slow electron tunneling, but could act as high impedance signals useful in regulation. Tunneling simulations of the respiratory complexes provide clear illustrations of this simple engineering.
Moser
Christopher C
CC
The Johnson Research Foundation, Department of Biochemistry and Biophysics, University of Pennsylvania, 1005, Stellar-Chance Laboratories, 422, Curie Boulevard, Philadelphia, PA 19104-6059, USA. moserc@mail.med.upenn.edu
Farid
Tammer A
TA
Chobot
Sarah E
SE
Dutton
P Leslie
PL
D000818:Animals; D002417:Cattle; D003067:Coenzymes / Q000737:chemistry; D004579:Electron Transport / Q000502:physiology; D042967:Electron Transport Complex I / Q000378:metabolism; D014450:Electron Transport Complex III / Q000378:metabolism; D003576:Electron Transport Complex IV / Q000737:chemistry; D008928:Mitochondria / Q000378:metabolism*; D051336:Mitochondrial Membranes / Q000378:metabolism; D013552:Swine
D003067:Coenzymes; D003576:Electron Transport Complex IV; D042967:Electron Transport Complex I; D014450:Electron Transport Complex III