Transient accumulation of elastic energy in proton translocating ATP synthase

FEBS Letters

Junge, Wolfgang¹  Cherepanov, Dmitry A.¹  Mulkidjanian, Armen Y.¹ 

[1]Division of Biophysics, Faculty of Biology/Chemistry, University of Osnabrück, D-49069 Osnabrück, Germany

关键词: ATP synthase;    Elastic energy;    Kinetic model;   

DOI  :  10.1016/S0014-5793(99)00386-5

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

ATP synthase is conceived as a rotatory engine with two reversible drives, the proton-transporting membrane portion, F₀, and the catalytic peripheral portion, F₁. They are mounted on a central shaft (subunit γ) and held together by an eccentric bearing. It is established that the hydrolysis of three molecules of ATP in F₁ drives the shaft over a full circle in three steps of 120° each. Proton flow through F₀ probably generates a 12-stepped rotation of the shaft so that four proton-translocating steps of 30° each drive the synthesis of one molecule of ATP. We addressed the elasticity of the transmission between F₀ and F₁ in a model where the four smaller steps in F₀ load a torsional spring which is only released under liberation of ATP from F₁. The kinetic model of an elastic ATP synthase described a wealth of published data on the synthesis/hydrolysis of ATP by F₀F₁ and on proton conduction by F₀ as function of the pH and the protonmotive force. The pK values of the proton-carrying group interacting with the acidic and basic sides of the membrane were estimated as 5.3–6.4 and 8.0–8.3, respectively.

【 授权许可】

Unknown