期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2020
卷号：117
期号：17
页码：9349-9355
DOI：10.1073/pnas.2001572117
出版社：The National Academy of Sciences of the United States of America
摘要：Mitochondria metabolize almost all the oxygen that we consume, reducing it to water by cytochrome c oxidase (C c O). C c O maximizes energy capture into the protonmotive force by pumping protons across the mitochondrial inner membrane. Forty years after the H /e − stoichiometry was established, a consensus has yet to be reached on the route taken by pumped protons to traverse C c O’s hydrophobic core and on whether bacterial and mitochondrial C c Os operate via the same coupling mechanism. To resolve this, we exploited the unique amenability to mitochondrial DNA mutagenesis of the yeast Saccharomyces cerevisiae to introduce single point mutations in the hydrophilic pathways of C c O to test function. From adenosine diphosphate to oxygen ratio measurements on preparations of intact mitochondria, we definitely established that the D-channel, and not the H-channel, is the proton pump of the yeast mitochondrial enzyme, supporting an identical coupling mechanism in all forms of the enzyme.
关键词：mitochondria ; cytochrome c oxidase ; H/e stoichiometry ; proton pumping ; ADP/O ratio
