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Sci Rep. 2017 Apr 20;7(1):974. doi: 10.1038/s41598-017-01129-0.

The tarantula toxin β/δ-TRTX-Pre1a highlights the importance of the S1-S2 voltage-sensor region for sodium channel subtype selectivity.

Author information

1
Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, 4072, Australia.
2
Discipline of Pharmacology, University of Sydney, Camperdown, NSW, 2006, Australia.
3
Novo Nordisk A/S, Copenhagen Area, Capital Region, Denmark.
4
Harvard Medical School, Children's Hospital, 300 Longwood Ave, Boston, MA, 02115, United States.
5
Department of Physiology and Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland, 21205, USA.
6
Pain Management Research Institute, University of Sydney, St Leonards, NSW, 2006, Australia.
7
Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, 2522, Australia.
8
Centre for Advanced Imaging & School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, QLD, 4072, Australia.
9
Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, 4072, Australia. l.rash@uq.edu.au.
10
School of Biomedical Sciences, The University of Queensland, St Lucia, 4072, QLD, Australia. l.rash@uq.edu.au.

Abstract

Voltage-gated sodium (NaV) channels are essential for the transmission of pain signals in humans making them prime targets for the development of new analgesics. Spider venoms are a rich source of peptide modulators useful to study ion channel structure and function. Here we describe β/δ-TRTX-Pre1a, a 35-residue tarantula peptide that selectively interacts with neuronal NaV channels inhibiting peak current of hNaV1.1, rNaV1.2, hNaV1.6, and hNaV1.7 while concurrently inhibiting fast inactivation of hNaV1.1 and rNaV1.3. The DII and DIV S3-S4 loops of NaV channel voltage sensors are important for the interaction of Pre1a with NaV channels but cannot account for its unique subtype selectivity. Through analysis of the binding regions we ascertained that the variability of the S1-S2 loops between NaV channels contributes substantially to the selectivity profile observed for Pre1a, particularly with regards to fast inactivation. A serine residue on the DIV S2 helix was found to be sufficient to explain Pre1a's potent and selective inhibitory effect on the fast inactivation process of NaV1.1 and 1.3. This work highlights that interactions with both S1-S2 and S3-S4 of NaV channels may be necessary for functional modulation, and that targeting the diverse S1-S2 region within voltage-sensing domains provides an avenue to develop subtype selective tools.

PMID:
28428547
PMCID:
PMC5430537
DOI:
10.1038/s41598-017-01129-0
[Indexed for MEDLINE]
Free PMC Article

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