Three‐stepped rotation of subunits γ and ϵ in single molecules of F‐ATPase as revealed by polarized, confocal fluorometry

FEBS Letters

Junge, Wolfgang¹  Engelbrecht, Siegfried¹  Häsler, Katrin¹ 

[1] Div. of Biophysics, Dept. Biology/Chemistry, Universität Osnabrück, D-49069 Osnabrück, Germany

关键词: ATP synthase;    Single molecule;    Rotation;    Molecular motor;   

DOI  :  10.1016/S0014-5793(98)00358-5

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The proton translocating ATP synthase is conceived as a rotatory molecular engine. ATP hydrolysis by its headpiece, CF₁, drives the rotation of subunit γ relative to the hexagonally arranged large subunits, (αβ)₃. We investigated transition states of the rotatory drive by polarized confocal fluorometry (POCOF) as applied to single molecules of engineered, immobilized and load-free spinach-CF₁. We found that the hydrolysis of ATP caused the stepped and sequential progression of subunit γ through three discrete angular positions, with the transition states of γ being too shortlived for detection. We also observed the stepped motion of ϵ, whereas δ was immobile as (αβ)₃.

【 授权许可】

Unknown