Faculty Collaboration Database

Calmodulin-induced Conformational Control and Allostery Underlying Neuronal Nitric Oxide Synthase Activation. J Mol Biol 2018 Mar 30;430(7):935-947

Date

02/20/2018

Pubmed ID

29458127

DOI

10.1016/j.jmb.2018.02.003

Scopus ID

2-s2.0-85042563266 (requires institutional sign-in at Scopus site)   16 Citations

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.

Author List

Hanson QM, Carley JR, Gilbreath TJ, Smith BC, Underbakke ES

Author

Brian C. Smith PhD Associate Professor in the Biochemistry department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Allosteric Regulation
Calmodulin
Catalytic Domain
Deuterium Exchange Measurement
Enzyme Activation
Humans
Nitric Oxide Synthase Type I
Protein Conformation