Rotation mechanism of F1-ATPase: Crucial importance of the water entropy effect

Takashi Yoshidome, Yuko Ito, Mitsunori Ikeguchi, Masahiro Kinoshita

研究成果: Article査読

30 被引用数 (Scopus)

抄録

We propose a novel picture of the rotation mechanism of F 1-ATPase, a rotary-motor protein complex. Entropy, which originates from the translational displacement of water molecules, is treated as the key factor in the proposal. We calculate the water entropy gains upon formation of the α-β, α-γ, and β-γ subunit pairs. The gain is given as the difference between the hydration entropy of a subunit pair and the sum of the hydration entropies of the separate subunits forming the pair. The calculation is made using a hybrid of a statistical-mechanical theory for molecular liquids and morphometric approach. The water entropy gain is considered as a measure of tightness of the packing at each subunit interface. The results are highly correlated with the numbers of stable contacts at the subunit interfaces estimated by a molecular dynamics simulation. We also calculate the hydration entropies of three different subcomplexes comprising the γ subunit, one of the β subunits, and two α subunits adjacent to them. The major finding is that the packing in F1-ATPase is highly asymmetrical, and this asymmetry is ascribed to the water entropy effect. We discuss how the rotation of the γ subunit is induced by such chemical processes as ATP binding, ATP hydrolysis, and release of the products. In our picture, the asymmetrical packing plays crucially important roles, and the rotation is driven by the water entropy effect.

本文言語English
ページ(範囲)4030-4039
ページ数10
ジャーナルJournal of the American Chemical Society
133
11
DOI
出版ステータスPublished - 2011 3 23
外部発表はい

ASJC Scopus subject areas

  • 触媒
  • 化学 (全般)
  • 生化学
  • コロイド化学および表面化学

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