The ATP synthase: the understood, the uncertain and the unknown
The ATP synthase: the understood, the uncertain and the unknown
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DOI：
10.1042/bst20110773
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发表时间：
2013-02-01
影响因子：
3.9
通讯作者：
Walker, John E.
中科院分区：
文献类型：
--
作者：
Walker, John E.
ATP酶是在细菌、叶绿体和线粒体的能量传递膜中发现的多蛋白复合物。它们采用跨膜质子动力Delta p作为能量来源来驱动机械旋转机制，该机制导致从ADP和Pi化学合成ATP。它们的总体架构、组织和机械原理大多已经确立，但其他特征还不太清楚。例如，来自细菌、线粒体和叶绿体的ATP酶在调节其活性的机制上是不同的，这些不同机制的分子基础及其生理作用才刚刚开始出现。另一个缺乏分子描述的关键特征是如何产生由Δ p驱动的旋转，以及旋转如何将能量传递到酶的催化位点以在旋转期间产生步进作用。一个令人惊讶但解释不完全的推论是，基于酶转子中c环的对称性，ATP合酶制造ATP分子所需的能量并不具有普适值。来自多细胞生物的ATP酶需要最少的能量，而在单细胞生物和叶绿体中制造ATP分子所需的能量更高，并且已经计算了一系列值。最后，越来越多的证据表明ATP酶在线粒体内膜中的其他作用。在这里，酶可能与特定的脂质形成超分子复合物，这些复合物可能有助于甚至决定嵴的形成。
The ATP synthases are multiprotein complexes found in the energy-transducing membranes of bacteria, chloroplasts and mitochondria. They employ a transmembrane protonmotive force, Delta p, as a source of energy to drive a mechanical rotary mechanism that leads to the chemical synthesis of ATP from ADP and Pi. Their overall architecture, organization and mechanistic principles are mostly well established, but other features are less well understood. For example, ATP synthases from bacteria, mitochondria and chloroplasts differ in the mechanisms of regulation of their activity, and the molecular bases of these different mechanisms and their physiological roles are only just beginning to emerge. Another crucial feature lacking a molecular description is how rotation driven by Delta p is generated, and how rotation transmits energy into the catalytic sites of the enzyme to produce the stepping action during rotation. One surprising and incompletely explained deduction based on the symmetries of c-rings in the rotor of the enzyme is that the amount of energy required by the ATP synthase to make an ATP molecule does not have a universal value. ATP synthases from multicellular organisms require the least energy, whereas the energy required to make an ATP molecule in unicellular organisms and chloroplasts is higher, and a range of values has been calculated. Finally, evidence is growing for other roles of ATP synthases in the inner membranes of mitochondria. Here the enzymes form supermolecular complexes, possibly with specific lipids, and these complexes probably contribute to, or even determine, the formation of the cristae.