文章基本信息

标题：Structural Changes and Proton Transfer in Cytochrome c Oxidase
本地全文：下载
作者：Jóhanna Vilhjálmsdóttir ; Ann-Louise Johansson ; Peter Brzezinski 等
期刊名称：Scientific Reports
电子版ISSN：2045-2322
出版年度：2015
卷号：5
DOI：10.1038/srep12047
出版社：Springer Nature
摘要：In cytochrome c oxidase electron transfer from cytochrome c to O₂ is linked to transmembrane proton pumping, which contributes to maintaining a proton electrochemical gradient across the membrane. The mechanism by which cytochrome c oxidase couples the exergonic electron transfer to the endergonic proton translocation is not known, but it presumably involves local structural changes that control the alternating proton access to the two sides of the membrane. Such redox-induced structural changes have been observed in X-ray crystallographic studies at residues 423–425 (in the R. sphaeroides oxidase), located near heme a . The aim of the present study is to investigate the functional effects of these structural changes on reaction steps associated with proton pumping. Residue Ser425 was modified using site-directed mutagenesis and time-resolved spectroscopy was used to investigate coupled electron-proton transfer upon reaction of the oxidase with O₂. The data indicate that the structural change at position 425 propagates to the D proton pathway, which suggests a link between redox changes at heme a and modulation of intramolecular proton-transfer rates.