Asymmetry of rotational catalysis of single membrane-bound F0F1-ATP synthase
Asymmetry of rotational catalysis of single membrane-bound F0F1-ATP synthase
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单膜结合 F0F1-ATP 合酶旋转催化的不对称性
DOI：
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发表时间：
2005
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影响因子：
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通讯作者：
M. Boersch
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作者：
N. Zarrabi;B. Zimmermann;M. Diez;P. Graeber;J. Wrachtrup;M. Boersch
细胞“能量货币”ATP的合成由膜结合的F0 F1-ATP酶催化。在F1部分中的三个结合位点处的化学反应通过亚基的内部旋转耦合到通过膜整合的F0部分的质子易位。我们通过单分子荧光共振能量转移（FRET）研究了“转子”的ε亚基相对于“定子”的b亚基的旋转运动。在ATP水解过程中ε的旋转分为三个主要步骤，其中恒定的FRET水平对应于三个结合位点。根据“转子”的相对取向，观察到各个结合位点的不同催化活性。FRET信号的计算机模拟和ε的非均匀分布取向强烈证实了F0 F1-ATP合酶催化的不对称性。
Synthesis of the cellular 'energy currency' ATP is catalyzed by membrane-bound F0F1-ATP synthases. The chemical reaction at three binding sites in the F1 part is coupled to proton translocation through the membrane-integrated F0 part by an internal rotation of subunits. We examined the rotary movements of the ε-subunit of the 'rotor' with respect to the b-subunits of the 'stator' by single-molecule fluorescence resonance energy transfer (FRET). Rotation of ε during ATP hydrolysis is divided into three major steps with constant FRET level corresponding to three binding sites. Different catalytic activities of the individual binding sites were observed depending on the relative orientation of the 'rotor'. Computer simulations of the FRET signals and non-equally distributed orientations of ε strongly corroborate asymmetry of catalysis in F0F1-ATP synthase.