Calmodulin-induced Conformational Control and Allostery Underlying Neuronal Nitric Oxide Synthase Activation

JOURNAL OF MOLECULAR BIOLOGY

卷:430

Article

Hanson, Quinlin M.¹  Carley, Jeffrey R.¹  Gilbreath, Tyler J.¹  Smith, Brian C.²  Underbakke, Eric S.¹ 

[1] Iowa State Univ, Roy J Carver Dept Biochem Biophys & Mol Biol, Ames, IA 50011 USA

[2] Med Coll Wisconsin, Dept Biochem, Milwaukee, WI 53226 USA

关键词: hydrogen-deuterium exchange;    mass spectrometry;    allosteric communication;    nitric oxide signaling;   

DOI  :  10.1016/j.jmb.2018.02.003

来源: Elsevier

【 摘 要 】

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.

【 授权许可】

Free