Calmodulin-induced Conformational Control and Allostery Underlying Neuronal Nitric Oxide Synthase Activation
Calmodulin-induced Conformational Control and Allostery Underlying Neuronal Nitric Oxide Synthase Activation
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DOI：
10.1016/j.jmb.2018.02.003
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发表时间：
2018-03-30
影响因子：
5.6
通讯作者：
Underbakke, Eric S.
中科院分区：
文献类型：
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作者：
Hanson, Quinlin M.;Carley, Jeffrey R.;Underbakke, Eric S.
一氧化氮合酶（NOS）是一氧化氮信号的主要产生者，控制着多种生理过程，如神经传递和血管舒张。NOS激活取决于在其加氧酶和还原酶结构域之间的接头处的Ca 2 +/钙调蛋白结合，以诱导协调结构域间电子转移的大的构象变化。然而，激活全长NOS的结构动力学仍然不明确。采用氢-氘交换质谱，我们揭示了神经元NOS激活钙调蛋白和磷酸化调节的机制。我们证明，钙调素结合命令还原酶和加氧酶结构域之间的连接，暴露FMN子域，并elerosis一个更动态的加氧酶活性位点。此外，我们证明，磷酸化部分模拟钙调蛋白激活，通过远程变构调节神经元NOS活性。钙调素结合和磷酸化最终促进更动态的全酶，同时协调结构域间的通信和电子转移。(C)2018爱思唯尔有限公司版权所有
Nitric oxide synthase (NOS) is the primary generator of nitric oxide signals controlling diverse physiological processes such as neurotransmission and vasodilation. NOS activation is contingent on Ca2+/calmodulin binding at a linker between its oxygenase and reductase domains to induce large conformational changes that orchestrate inter-domain electron transfer. However, the structural dynamics underlying activation of full-length NOS remain ambiguous. Employing hydrogen-deuterium exchange mass spectrometry, we reveal mechanisms underlying neuronal NOS activation by calmodulin and regulation by phosphorylation. We demonstrate that calmodulin binding orders the junction between reductase and oxygenase domains, exposes the FMN subdomain, and elicits a more dynamic oxygenase active site. Furthermore, we demonstrate that phosphorylation partially mimics calmodulin activation to modulate neuronal NOS activity via long-range allostery. Calmodulin binding and phosphorylation ultimately promote a more dynamic holoenzyme while coordinating inter-domain communication and electron transfer. (C) 2018 Elsevier Ltd. All rights reserved.