Format

Send to

Choose Destination
J Mol Biol. 2018 Mar 30;430(7):935-947. doi: 10.1016/j.jmb.2018.02.003. Epub 2018 Feb 17.

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

Author information

1
Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA 50011, USA.
2
Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
3
Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA 50011, USA. Electronic address: esu@iastate.edu.

Abstract

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.

KEYWORDS:

allosteric communication; hydrogen–deuterium exchange; mass spectrometry; nitric oxide signaling

PMID:
29458127
DOI:
10.1016/j.jmb.2018.02.003
[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Elsevier Science
Loading ...
Support Center