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ヨコヤマ ケン
YOKOYAMA KEN
横山 謙 所属 京都産業大学 生命科学部 先端生命科学科 職種 教授 |
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| 言語種別 | 英語 |
| 発行・発表の年月 | 2014/09 |
| 形態種別 | 研究論文 |
| 査読 | 査読あり |
| 標題 | F-subunit reinforces torque generation in V-ATPase |
| 執筆形態 | その他 |
| 掲載誌名 | EUROPEAN BIOPHYSICS JOURNAL WITH BIOPHYSICS LETTERS |
| 出版社・発行元 | SPRINGER |
| 巻・号・頁 | 43(8-9),pp.415-422 |
| 著者・共著者 | Jun-ichi Kishikawa,Akihiko Seino,Atsuko Nakanishi,Naciye Esma Tirtom,Hiroyuki Noji,Ken Yokoyama,Kumiko Hayashi |
| 概要 | Vacuolar-type H+-pumping ATPases (V-ATPases) perform remarkably diverse functions in eukaryotic organisms. They are present in the membranes of many organelles and regulate the pH of several intracellular compartments. A family of V-ATPases is also present in the plasma membranes of some bacteria. Such V-ATPases function as ATP-synthases. Each V-ATPase is composed of a water-soluble domain (V-1) and a membrane-embedded domain (V-o). The ATP-driven rotary unit, V, is composed of A, B, D, and F subunits. The rotary shaft (the DF subcomplex) rotates in the central cavity of the A(3)B(3)-ring (the catalytic hexamer ring). The D-subunit, which has a coiled-coil domain, penetrates into the ring, while the F-subunit is a globular-shaped domain protruding from the ring. The minimal ATP-driven rotary unit of V is comprised of the A(3)B(3)D subunits, and we therefore investigated how the absence of the globular-shaped F-subunit affects the rotary torque generation of V. Using a single-molecule technique, we observed the motion of the rotary motors. To obtain the torque values, we then analyzed the measured motion trajectories based on the fluctuation theorem, which states that the law of entropy production in non-equilibrium conditions and has been suggested as a novel and effective method for measuring torque. The measured torque of A(3)B(3)D was half that of the wild-type V-1, and full torque was recovered in the mutant V-1, in which the F-subunit was genetically fused with the D-subunit, indicating that the globular-shaped F-subunit reinforces torque generation in V-1. |
| DOI | 10.1007/s00249-014-0973-x |
| ISSN | 0175-7571/1432-1017 |
| PMID | 25012687 |