Grüber Gerhard, Manimekalai Malathy Sony Subramanian, Mayer Florian, Müller Volker
School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Republic of Singapore.
School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Republic of Singapore.
Biochim Biophys Acta. 2014 Jun;1837(6):940-52. doi: 10.1016/j.bbabio.2014.03.004. Epub 2014 Mar 17.
Archaea live under different environmental conditions, such as high salinity, extreme pHs and cold or hot temperatures. How energy is conserved under such harsh environmental conditions is a major question in cellular bioenergetics of archaea. The key enzymes in energy conservation are the archaeal A1AO ATP synthases, a class of ATP synthases distinct from the F1FO ATP synthase ATP synthase found in bacteria, mitochondria and chloroplasts and the V1VO ATPases of eukaryotes. A1AO ATP synthases have distinct structural features such as a collar-like structure, an extended central stalk, and two peripheral stalks possibly stabilizing the A1AO ATP synthase during rotation in ATP synthesis/hydrolysis at high temperatures as well as to provide the storage of transient elastic energy during ion-pumping and ATP synthesis/-hydrolysis. High resolution structures of individual subunits and subcomplexes have been obtained in recent years that shed new light on the function and mechanism of this unique class of ATP synthases. An outstanding feature of archaeal A1AO ATP synthases is their diversity in size of rotor subunits and the coupling ion used for ATP synthesis with H(+), Na(+) or even H(+) and Na(+) using enzymes. The evolution of the H(+) binding site to a Na(+) binding site and its implications for the energy metabolism and physiology of the cell are discussed.
古菌生活在不同的环境条件下，如高盐度、极端酸碱度以及寒冷或炎热的温度环境。在如此恶劣的环境条件下如何保存能量是古菌细胞生物能量学中的一个主要问题。能量保存中的关键酶是古菌A1AO ATP合酶，这是一类与细菌、线粒体和叶绿体中发现的F1FO ATP合酶以及真核生物的V1VO ATP酶不同的ATP合酶。A1AO ATP合酶具有独特的结构特征，如衣领状结构、延长的中央轴以及两个外周轴，这些结构可能在高温下ATP合成/水解过程中旋转时稳定A1AO ATP合酶，同时在离子泵浦以及ATP合成/水解过程中提供瞬态弹性能量的储存。近年来已经获得了单个亚基和亚复合物的高分辨率结构，这为这类独特的ATP合酶的功能和机制提供了新的线索。古菌A1AO ATP合酶的一个突出特点是其转子亚基大小的多样性以及用于ATP合成的偶联离子，包括使用H(+)、Na(+)的酶，甚至是同时使用H(+)和Na(+)的酶。本文讨论了H(+)结合位点向Na(+)结合位点的进化及其对细胞能量代谢和生理学的影响。
