Single-Molecule Analysis of the Rotation of F1-ATPase under High Hydrostatic Pressure

この論文にアクセスする

この論文をさがす

抄録

F1-ATPase is the water-soluble part of ATP synthase and is an ATP-driven rotary molecular motor that rotates the rotary shaft against the surrounding stator ring, hydrolyzing ATP. Although the mechanochemical coupling mechanism of F1-ATPase has been well studied, the molecular details of individual reaction steps remain unclear. In this study, we conducted a single-molecule rotation assay of F1 from thermophilic bacteria under various pressures from 0.1 to 140 MPa. Even at 140 MPa, F1 actively rotated with regular 120° steps in a counterclockwise direction, showing high conformational stability and retention of native properties. Rotational torque was also not affected. However, high hydrostatic pressure induced a distinct intervening pause at the ATP-binding angles during continuous rotation. The pause was observed under both ATP-limiting and ATP-saturating conditions, suggesting that F1 has two pressure-sensitive reactions, one of which is evidently ATP binding. The rotation assay using a mutant F1(βE190D) suggested that the other pressure-sensitive reaction occurs at the same angle at which ATP binding occurs. The activation volumes were determined from the pressure dependence of the rate constants to be +100 Å3 and +88 Å3 for ATP binding and the other pressure-sensitive reaction, respectively. These results are discussed in relation to recent single-molecule studies of F1 and pressure-induced protein unfolding.

収録刊行物

  • Biophysical Journal

    Biophysical Journal 105(7), 1635-1642, 2013-10-01

各種コード

  • NII論文ID(NAID)
    120005328380
  • NII書誌ID(NCID)
    AA00566095
  • 本文言語コード
    EN
  • 資料種別
    Journal Article
  • ISSN
    0006-3495
  • データ提供元
    IR 
ページトップへ