ATP-induced structural change of the thermosome is temperature-dependent
ATP-induced structural change of the thermosome is temperature-dependent
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DOI：
10.1006/jsbi.2001.4373
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发表时间：
2001-08-01
影响因子：
3
通讯作者：
May, RP
中科院分区：
文献类型：
--
作者：
Gutsche, I;Holzinger, J;May, RP
伴侣蛋白的蛋白质折叠由 ATP 结合和水解提供动力。 ATP 酶活性通过一系列构象重排驱动折叠机，这些构象重排对来自大肠杆菌的 I 类伴侣蛋白 GroEL 进行了广泛描述，但对 II 类伴侣蛋白仍知之甚少。后者的古菌热体和真核 TMUCCT 功能独立于 GroES 样辅伴侣蛋白，并且被认为依赖其自身顶端域的突起以 ATP 控制的方式打开和关闭。在这里，我们使用小角中子散射来分析来自嗜酸热原体的重组α-only和天然αβ-热体在溶液中ATP酶循环时的结构变化。我们表明，特定的高盐条件（而不是单独存在 MgATP）会诱导更高阶热体聚集体的形成。热囊的开闭转变机制强烈依赖于温度。 ATP 与伴侣蛋白的结合似乎是一个两步过程：在较低温度下，ATP 热体的开放状态占主导地位，而加热到生理温度会导致其切换到关闭状态。我们的数据揭示了两组伴侣蛋白的 ATP 酶循环之间的相似性，并使我们能够提出热体作用模型。 (C) 2001 年学术出版社。
Protein folding by chaperonins is powered by ATP binding and hydrolysis. ATPase activity drives the folding machine through a series of conformational rearrangements, extensively described for the group I chaperonin GroEL from Escherichia coli but still poorly understood for the group II chaperonins. The latter-archaeal thermosome and eukaryotic TMUCCT-function independently of a GroES-like cochaperonin and are proposed to rely on protrusions of their own apical domains for opening and closure in an ATP-controlled fashion. Here we use small-angle neutron scattering to analyze structural changes of the recombinant a-only and the native alpha beta -thermosome from Thermoplasma acidophilum upon their ATPase cycling in solution. We show that specific high-salt conditions, but not the presence of MgATP alone, induce formation of higher order thermosome aggregates. The mechanism of the open-closed transition of the thermosome is strongly temperature-dependent. ATP binding to the chaperonin appears to be a two-step process: at lower temperatures an open state of the ATP-thermosome is predominant, whereas heating to physiological temperatures induces its switching to a closed state. Our data reveal an analogy between the ATPase cycles of the two groups of chaperonins and enable us to put forward a model of thermosome action. (C) 2001 Academic Press.