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Protonation-State-Dependent Communication in Cytochrome c Oxidase

Helabad MB, Ghane T, Reidelbach M, Woelke AL, Knapp EW, Imhof P (2017)

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Publication Type: Journal article

Publication year: 2017

Journal

Book Volume: 113

Pages Range: 817-828

Journal Issue: 4

DOI: 10.1016/j.bpj.2017.07.005

Abstract

Proton transfer in cytochrome c oxidase from the cellular inside to the binuclear redox center (BNC) can occur through two distinct pathways, the D- and K-channels. For the protein to function as both a redox enzyme and a proton pump, proton transfer into the protein toward the BNC or toward a proton loading site (and ultimately through the membrane) must be highly regulated. The PR → F transition is the first step in a catalytic cycle that requires proton transfer from the bulk at the N-side to the BNC. Molecular dynamics simulations of the PR → F intermediate of this transition, with 16 different combinations of protonation states of key residues in the D- and K-channel, show the impact of the K-channel on the D-channel to be protonation-state dependent. Strength as well as means of communication, correlations in positions, or communication along the hydrogen-bonded network depends on the protonation state of the K-channel residue K362. The conformational and hydrogen-bond dynamics of the D-channel residue N139 is regulated by an interplay of protonation in the D-channel and K362. N139 thus assumes a gating function by which proton passage through the D-channel toward E286 is likely facilitated for states with protonated K362 and unprotonated E286. In contrast, proton passage through the D-channel is hindered by N139's preference for a closed conformation in situations with protonated E286.

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How to cite

APA:

Helabad, M.B., Ghane, T., Reidelbach, M., Woelke, A.L., Knapp, E.W., & Imhof, P. (2017). Protonation-State-Dependent Communication in Cytochrome c Oxidase. Biophysical Journal, 113(4), 817-828. https://dx.doi.org/10.1016/j.bpj.2017.07.005

MLA:

Helabad, Mandi Bagherpoor, et al. "Protonation-State-Dependent Communication in Cytochrome c Oxidase." Biophysical Journal 113.4 (2017): 817-828.

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