Correlation Engine 2.0
Clear Search sequence regions

Cytochrome bo is a terminal quinol oxidase in the aerobic respiratory chain of Escherichia coli. Subunit I binds all four redox centers, and electrons are transferred from quinols to high-spin heme o and Cu(B) through a bound uniquinone-8 and low-spin heme b. To explore the role of conserved charged amino acid residues, we examined the one-electron transfer processes in subunit I mutants. We found that all the mutants examined increased the electron transfer rate from the bound quinone to heme b more than 40-fold. Tyr288 and Lys362 are key residues in the K-channel for charge compensation of the heme o-Cu(B) binuclear center with protons. The Tyr288Phe and Lys362Gln mutants showed 100-fold decreases in heme b-to-heme o electron transfer, accompanied by large increases in the redox potential of heme o. Our results indicate that electromagnetic coupling of hemes is important for facilitated heme-heme electron transfer in cytochrome bo.


Kazuo Kobayashi, Seiichi Tagawa, Tatsushi Mogi. Electron transfer processes in subunit I mutants of cytochrome bo quinol oxidase in Escherichia coli. Bioscience, biotechnology, and biochemistry. 2009 Jul;73(7):1599-603

Expand section icon Mesh Tags

Expand section icon Substances

PMID: 19584547

View Full Text