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Article Dans Une Revue Scientific Reports Année : 2019

Proton-transfer pathways in the mitochondrial S. cerevisiae cytochrome c oxidase

Résumé

In cytochrome c oxidase (CytcO) reduction of O2 to water is linked to uptake of eight protons from the negative side of the membrane: four are substrate protons used to form water and four are pumped across the membrane. In bacterial oxidases, the substrate protons are taken up through the K and the D proton pathways, while the pumped protons are transferred through the D pathway. On the basis of studies with CytcO isolated from bovine heart mitochondria, it was suggested that in mitochondrial CytcOs the pumped protons are transferred though a third proton pathway, the H pathway, rather than through the D pathway. Here, we studied these reactions in S. cerevisiae CytcO, which serves as a model of the mammalian counterpart. We analyzed the effect of mutations in the D (Asn99Asp and Ile67Asn) and H pathways (Ser382Ala and Ser458Ala) and investigated the kinetics of electron and proton transfer during the reaction of the reduced CytcO with O2. No effects were observed with the H pathway variants while in the D pathway variants the functional effects were similar to those observed with the R. sphaeroides CytcO. The data indicate that the S. cerevisiae CytcO uses the D pathway for proton uptake and presumably also for proton pumping.
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Dates et versions

hal-02431238 , version 1 (10-11-2020)

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Markus L. Björck, Jóhanna Vilhjálmsdóttir, Andrew M. Hartley, Brigitte Meunier, Linda Näsvik Öjemyr, et al.. Proton-transfer pathways in the mitochondrial S. cerevisiae cytochrome c oxidase. Scientific Reports, 2019, 9 (1), pp.20207. ⟨10.1038/s41598-019-56648-9⟩. ⟨hal-02431238⟩
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