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Hokkaido University Collection of Scholarly and Academic Papers >
Graduate School of Science / Faculty of Science >
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Osmotic pressure effects identify dehydration upon cytochrome c-cytochrome c oxidase complex formation contributing to a specific electron pathway formation
| 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)
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Submitter: 石森 浩一郎
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