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Osmotic pressure effects identify dehydration upon cytochrome c-cytochrome c oxidase complex formation contributing to a specific electron pathway formation

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Biochem. J.477-8_1565–1578.pdf3.37 MBPDFView/Open
Please use this identifier to cite or link to this item:http://hdl.handle.net/2115/81095

Title: Osmotic pressure effects identify dehydration upon cytochrome c-cytochrome c oxidase complex formation contributing to a specific electron pathway formation
Authors: Sato, Wataru Browse this author
Hitaoka, Seiji Browse this author
Uchida, Takeshi Browse this author
Shinzawa-Itoh, Kyoko Browse this author
Yoshizawa, Kazunari Browse this author
Yoshikawa, Shinya Browse this author
Ishimori, Koichiro Browse this author →KAKEN DB
Keywords: complex IV
cytochrome c
dehydration
electron transfer
osmotic pressure
Issue Date: 30-Apr-2020
Publisher: Portland Press Ltd
Journal Title: Biochemical journal
Volume: 477
Issue: 8
Start Page: 1565
End Page: 1578
Publisher DOI: 10.1042/BCJ20200023
Abstract: In the electron transfer (ET) reaction from cytochrome c (Cyt c) to cytochrome c oxidase (CcO), we determined the number and sites of the hydration water released from the protein surface upon the formation of the ET complex by evaluating the osmotic pressure dependence of kinetics for the ET from Cyt c to CcO. We identified that similar to 20 water molecules were dehydrated in complex formation under turnover conditions, and systematic Cyt c mutations in the interaction site for CcO revealed that nearly half of the released hydration water during the complexation were located around Ile81, one of the hydrophobic amino acid residues near the exposed heme periphery of Cyt c. Such a dehydration dominantly compensates for the entropy decrease due to the association of Cyt c with CcO, resulting in the entropy-driven ET reaction. The energetic analysis of the interprotein interactions in the ET complex predicted by the docking simulation suggested the formation of hydrophobic interaction sites surrounding the exposed heme periphery of Cyt c in the Cyt c-CcO interface (a 'molecular breakwater'). Such sites would contribute to the formation of the hydrophobic ET pathway from Cyt c to CcO by blocking water access from the bulk water phase.
Type: article (author version)
URI: http://hdl.handle.net/2115/81095
Appears in Collections:理学院・理学研究院 (Graduate School of Science / Faculty of Science) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)

Submitter: 石森 浩一郎

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