ATP-induced electron transfer by redox-selective partner recognition
ATP-induced electron transfer by redox-selective partner recognition
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DOI：
10.1038/ncomms5626
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发表时间：
2014-08-01
影响因子：
16.6
通讯作者：
Dobbek, Holger
中科院分区：
文献类型：
--
作者：
Hennig, Sandra E.;Goetzl, Sebastian;Dobbek, Holger
热力学上不利的电子转移是通过与供能反应耦合而实现的。能量如何从放能过程转换为吸能过程在很大程度上是未知的。在这里，我们提供了 B-12 依赖性甲基转移酶还原激活中能量转导过程的结构基础。一个电子从激活酶到钴胺素辅因子的转移是一个充满能量的过程，并且依赖于与 ATP 酶反应的耦合。我们的结果表明，除了依赖于氧化态的络合物形成之外，耦合的关键是电子转移的构象门控。络合物的形成导致配体在电子接受钴离子处发生取代。添加 ATP 通过引发构象变化来启动电子转移，从而破坏复合物的稳定性。我们展示了电子接受 Co2+ 的重塑如何促进 ATP 依赖性电子转移；这是其他电子传递 ATP 酶中未见的有效策略。
Thermodynamically unfavourable electron transfers are enabled by coupling to an energy-supplying reaction. How the energy is transduced from the exergonic to the endergonic process is largely unknown. Here we provide the structural basis for an energy transduction process in the reductive activation of B-12-dependent methyltransferases. The transfer of one electron from an activating enzyme to the cobalamin cofactor is energetically uphill and relies on coupling to an ATPase reaction. Our results demonstrate that the key to coupling is, besides the oxidation state-dependent complex formation, the conformational gating of the electron transfer. Complex formation induces a substitution of the ligand at the electron-accepting Co ion. Addition of ATP initiates electron transfer by provoking conformational changes that destabilize the complex. We show how remodelling of the electron-accepting Co2+ promotes ATP-dependent electron transfer; an efficient strategy not seen in other electron-transferring ATPases.