FARVER O, KRONECK PMH, ZUMFT WG, PECHT I
Allosteric control of internal
electron transfer in cytochrome cd1 nitrite reductase.
PNAS 100: 7622-7625 (2003)
Cytochrome cd1
nitrite reductase is a bifunctional multiheme enzyme catalyzing the
one-electron reduction of nitrite to nitric oxide and the four-electron
reduction of dioxygen to water. Kinetics and thermodynamics of the
internal electron transfer process in the Pseudomonas stutzeri enzyme
have been studied and found to be dominated by pronounced interactions
between the c and the d1 hemes. The
interactions are expressed both in dramatic changes in the internal
electron-transfer rates between these sites and in marked cooperativity
in their electron affinity. The results constitute a prime example of
intraprotein control of the electron-transfer rates by allosteric
interactions.