Evidence for fast electron transfer between the high-spin haems in cytochrome bd-I from Escherichia coli

19Citations
Citations of this article
24Readers
Mendeley users who have this article in their library.

Abstract

Cytochrome bd-I is one of the three proton motive force-generating quinol oxidases in the O2-dependent respiratory chain of Escherichia coli. It contains one low-spin haem (b558) and the two high-spin haems (b595 and d) as the redox-active cofactors. In order to examine the flash-induced intraprotein reverse electron transfer (the so-called "electron backflow"), CO was photolyzed from the ferrous haem d in one-electron reduced (b5583+b5953+d2+-CO) cytochrome bd-I, and the fully reduced (b5582+b5952+d2+-CO) oxidase as a control. In contrast to the fully reduced cytochrome bd-I, the transient spectrum of one-electron reduced oxidase at a delay time of 1.5 μs is clearly different from that at a delay time of 200 ns. The difference between the two spectra can be modeled as the electron transfer from haem d to haem b595 in 3-4% of the cytochrome bd-I population. Thus, the interhaem electron backflow reaction induced by photodissociation of CO from haem d in one-electron reduced cytochrome bd-I comprises two kinetically different phases: the previously unnoticed fast electron transfer from haem d to haem b595 within 0.2-1.5 μs and the slower well-defined electron equilibration with τ ∼16 μs. The major new finding of this work is the lack of electron transfer at 200 ns.

Cite

CITATION STYLE

APA

Siletsky, S. A., Rappaport, F., Poole, R. K., & Borisov, V. B. (2016). Evidence for fast electron transfer between the high-spin haems in cytochrome bd-I from Escherichia coli. PLoS ONE, 11(5). https://doi.org/10.1371/journal.pone.0155186

Register to see more suggestions

Mendeley helps you to discover research relevant for your work.

Already have an account?

Save time finding and organizing research with Mendeley

Sign up for free