Backbone resonance assignments of complexes of human voltage-dependent sodium channel NaV1.2 IQ motif peptide bound to apo calmodulin and to the C-domain fragment of apo calmodulin

Ryan Mahling; Adina Kilpatrick; Madeline Shea

doi:10.1007/s12104-017-9767-2

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Backbone resonance assignments of complexes of human voltage-dependent sodium channel NaV1.2 IQ motif peptide bound to apo calmodulin and to the C-domain fragment of apo calmodulin

Ryan Mahling, Adina Kilpatrick and Madeline Shea

Biomolecular NMR assignments, Vol.11(2), pp.297-303

10/2017

DOI: 10.1007/s12104-017-9767-2

PMCID: PMC5791537

PMID: 28823028

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https://www.ncbi.nlm.nih.gov/pmc/articles/5791537View

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Abstract

Human voltage-gated sodium channel NaV1.2 has a single pore-forming α-subunit and two transmembrane β-subunits. Expressed primarily in the brain, NaV1.2 is critical for initiation and propagation of action potentials. Milliseconds after the pore opens, sodium influx is terminated by inactivation processes mediated by regulatory proteins including calmodulin (CaM). Both calcium-free (apo) CaM and calcium-saturated CaM bind tightly to an IQ motif in the C-terminal tail of the α-subunit. Our thermodynamic studies and solution structure (2KXW) of a C-domain fragment of apo 13C,15N- CaM (CaMC) bound to an unlabeled peptide with the sequence of rat NaV1.2 IQ motif showed that apo CaMC (a) was necessary and sufficient for binding, and (b) bound more favorably than calcium-saturated CaMC. However, we could not monitor the NaV1.2 residues directly, and no structure of full-length CaM (including the N-domain of CaM (CaMN)) was determined. To distinguish contributions of CaMN and CaMC, we used solution NMR spectroscopy to assign the backbone resonances of a complex containing a 13C,15N-labeled peptide with the sequence of human NaV1.2 IQ motif (NaV1.2IQp) bound to apo 13C,15N-CaM or apo 13C,15N-CaMC. Comparing the assignments of apo CaM in complex with NaV1.2IQp to those of free apo CaM showed that residues within CaMC were significantly perturbed, while residues within CaMN were essentially unchanged. The chemical shifts of residues in NaV1.2IQp and in the C-domain of CaM were nearly identical regardless of whether CaMN was covalently linked to CaMC. This suggests that CaMN does not influence apo CaM binding to NaV1.2IQp.

Molecular Recognition

Physics

Polymer Sciences

Biochemistry, general

EF-hand protein

Allostery

Biological and Medical Physics, Biophysics

Domain interactions

Voltage-gated sodium channel

Details

Title: Subtitle: Backbone resonance assignments of complexes of human voltage-dependent sodium channel NaV1.2 IQ motif peptide bound to apo calmodulin and to the C-domain fragment of apo calmodulin
Creators: Ryan Mahling - Department of Biochemistry, Roy J. and Lucille A. Carver College of Medicine University of Iowa Iowa City IA 52242-1109 USA
Adina Kilpatrick - Department of Physics and Astronomy Drake University Des Moines IA 50311-4516 USA
Madeline Shea - Department of Biochemistry, Roy J. and Lucille A. Carver College of Medicine University of Iowa Iowa City IA 52242-1109 USA
Resource Type: Journal article
Publication Details: Biomolecular NMR assignments, Vol.11(2), pp.297-303
DOI: 10.1007/s12104-017-9767-2
PMID: 28823028
PMCID: PMC5791537
NLM abbreviation: Biomol NMR Assign
ISSN: 1874-2718
eISSN: 1874-270X
Publisher: Springer Netherlands; Dordrecht
Grant note: R01 GM57001 / National Institute of General Medical Sciences (http://dx.doi.org/10.13039/100000057) T32 NS045549 / National Institute of Neurological Disorders and Stroke (http://dx.doi.org/10.13039/100000065)
Language: English
Date published: 10/2017
Academic Unit: Molecular Physiology and Biophysics; Iowa Neuroscience Institute; Biochemistry and Molecular Biology
Record Identifier: 9984024535702771

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