Quantum Calculations of Electron Tunneling in Respiratory Complex III
Document Type
Article
Publication Title
Journal of Physical Chemistry B
Abstract
The most detailed and comprehensive to date study of electron transfer reactions in the respiratory complex III of aerobic cells, also known as bc1 complex, is reported. In the framework of the tunneling current theory, electron tunneling rates and atomistic tunneling pathways between different redox centers were investigated for all electron transfer reactions comprising different stages of the proton-motive Q-cycle. The calculations reveal that complex III is a smart nanomachine, which under certain conditions undergoes conformational changes gating electron transfer, or channeling electrons to specific pathways. One-electron tunneling approximation was adopted in the tunneling calculations, which were performed using hybrid Broken-Symmetry (BS) unrestricted DFT/ZINDO levels of theory. The tunneling orbitals were determined using an exact biorthogonalization scheme that uniquely separates pairs of tunneling orbitals with small overlaps out of the remaining Franck-Condon orbitals with significant overlap. Electron transfer rates in different redox pairs show exponential distance dependence, in agreement with the reported experimental data; some reactions involve coupled proton transfer. Proper treatment of a concerted two-electron bifurcated tunneling reaction at the Qo site is given.
First Page
14637
Last Page
14651
DOI
10.1021/acs.jpcb.5b09424
Publication Date
11-19-2015
Recommended Citation
Hagras, Muhammad A.; Hayashi, Tomoyuki; and Stuchebrukhov, Alexei A., "Quantum Calculations of Electron Tunneling in Respiratory Complex III" (2015). Basic Sciences Faculty Publications. 112.
https://doi.org/10.1021/acs.jpcb.5b09424
https://collections.uhsp.edu/basic-sciences_pubs/112