Allosteric control of internal electron transfer in cytochrome cd1 nitrite reductase.
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.
Farver
Ole
O
Department of Analytical Chemistry, Danish University of Pharmaceutical Sciences, DK-2100 Copenhagen, Denmark. of@dfh.dk
Kroneck
Peter M H
PM
Zumft
Walter G
WG
Pecht
Israel
I
D000495:Allosteric Site; D055592:Biophysical Phenomena; D001703:Biophysics; D003580:Cytochromes; D004579:Electron Transport; D003576:Electron Transport Complex IV / Q000737:chemistry* / Q000378:metabolism*; D004583:Electrons; D007700:Kinetics; D008962:Models, Theoretical; D009572:Nitrite Reductases / Q000737:chemistry* / Q000378:metabolism*; D011549:Pseudomonas / Q000201:enzymology; D013816:Thermodynamics; D013997:Time Factors
D003580:Cytochromes; D009572:Nitrite Reductases; C028123:nitrite reductase (NO-forming); D003576:Electron Transport Complex IV