Movements of the ε‐subunit during catalysis and activation in single membrane‐bound H+‐ATP synthase
Movements of the ε‐subunit during catalysis and activation in single membrane‐bound H+‐ATP synthase
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单膜结合 H+-ATP 合酶催化和激活过程中 ε 亚基的运动
DOI：
10.1038/sj.emboj.7600682
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发表时间：
2005
期刊：
影响因子：
--
通讯作者：
M. Börsch
中科院分区：
文献类型：
--
作者：
B. Zimmermann;M. Diez;N. Zarrabi;P. Gräber;M. Börsch
F0 F1-ATP酶催化细菌、叶绿体和线粒体中的质子转运偶联ATP合成。在这些复合物中，ε-亚基参与催化反应和酶的活化。将来自大肠杆菌的荧光标记的F0 F1掺入脂质体中。单分子荧光共振能量转移（FRET）显示，ε-亚基逐步旋转，显示出三个不同的距离，在外周柄的B-亚基。在ATP的合成和水解过程中，旋转方向相反。对每个FRET状态的停留时间的分析揭示了三个催化位点的不同反应性，这取决于旋转过程中ε的相对取向。在不存在核苷酸的情况下，通过酶的质子运输导致ε的构象变化。当酶失活时（即在没有底物或没有膜粘附的情况下），再次发现了三个距离，这与活性酶的距离不同。失活酶的三种状态分布不均匀。我们的结论是，活性-非活性转变与中央柄内的ε构象变化有关。
F0F1‐ATP synthases catalyze proton transport‐coupled ATP synthesis in bacteria, chloroplasts, and mitochondria. In these complexes, the ε‐subunit is involved in the catalytic reaction and the activation of the enzyme. Fluorescence‐labeled F0F1 from Escherichia coli was incorporated into liposomes. Single‐molecule fluorescence resonance energy transfer (FRET) revealed that the ε‐subunit rotates stepwise showing three distinct distances to the b‐subunits in the peripheral stalk. Rotation occurred in opposite directions during ATP synthesis and hydrolysis. Analysis of the dwell times of each FRET state revealed different reactivities of the three catalytic sites that depended on the relative orientation of ε during rotation. Proton transport through the enzyme in the absence of nucleotides led to conformational changes of ε. When the enzyme was inactive (i.e. in the absence of substrates or without membrane energization), three distances were found again, which differed from those of the active enzyme. The three states of the inactive enzyme were unequally populated. We conclude that the active–inactive transition was associated with a conformational change of ε within the central stalk.
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影响因子：
2.9
作者：
Díez-Sampedro,Ana;Loo,DonaldDF;Wright,ErnestM;Zampighi,GuidoA;Hirayama,BruceA
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DOI：
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发表时间：
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影响因子：
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作者：
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通讯作者：
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影响因子：
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作者：
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影响因子：
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作者：
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