| Structural highlights
Function
TXH4_CYRSC This lethal neurotoxin (without cyclization at position 53) inhibits neuronal voltage-gated sodium channel Nav1.2/SCN2A (IC(50)=10-150 nM), rNav1.3/SCN3A (IC(50)=338 nM), Nav1.6/SCN8A (IC(50)=117 nM), and hNav1.7/SCN9A (IC(50)=9.6-33 nM) (PubMed:18628201, PubMed:20855463, PubMed:25658507, PubMed:29703751,PubMed:31234412, PubMed:23760503). It inhibits activation of sodium channel by trapping the voltage sensor of domain II (DIIS4) in the closed configuration (PubMed:18628201, PubMed:23760503). The toxin neither shifts the Nav1.7/SCN9A activation curve nor modifies the slope factor (PubMed:20855463). It does not slow fast-inactivation of hNav1.7/SCN9A channels (PubMed:20855463). In addition, it has only a weak affinity for lipid membranes (PubMed:18054060, PubMed:29703751, PubMed:28115115). This toxin also exists with a pyroglutamate at position 53 (PubMed:23826086). The sole difference observed between modified (mHwTx-IV) and unmodified toxins is that moderate or high depolarization voltages (200 mV) permit the unmodified toxin to dissociate, whereas mHwTx-IV toxin does not dissociate, even at high depolarization voltages (PubMed:23826086). These data indicate that mHwTx-IV strongly binds to voltage sensor of sodium channel even at extreme depolarization voltages (PubMed:23826086).[1] [2] [3] [4] [5] [6] [7] [8] [9] [10]
Publication Abstract from PubMed
Venom-derived peptides have attracted much attention as potential lead molecules for pharmaceutical development. A well-known example is Huwentoxin-IV (HwTx-IV), a peptide toxin isolated from the venom of the Chinese bird-eating spider Haplopelma schmitdi. HwTx-IV was identified as a potent blocker of a human voltage-gated sodium channel (hNaV1.7), which is a genetically validated analgesic target. The peptide was promising as it showed high potency at NaV1.7 (IC50 ~26 nM) and selectivity over the cardiac NaV subtype (NaV1.5). Mutagenesis studies aimed at optimising the potency of the peptide resulted in the development of a triple-mutant of HwTx-IV (E1G, E4G, Y33W, m3-HwTx-IV) with significantly increased potency against hNaV1.7 (IC50 = 0.4 +/- 0.1 nM) without increased potency against hNaV1.5. The activity of m3-HwTx-IV against other NaV subtypes was, however, not investigated. Similarly, the structure of the mutant peptide was not characterised, limiting the interpretation of the observed increase in potency. In this study we produced isotope-labelled recombinant m3-HwTx-IV in E. coli, which enabled us to characterise the atomic-resolution structure and dynamics of the peptide by NMR spectroscopy. The results show that the structure of the peptide is not perturbed by the mutations, whilst the relaxation studies reveal that residues in the active site of the peptide undergo conformational exchange. Additionally, the NaV subtype selectivity of the recombinant peptide was characterised, revealing potent inhibition of neuronal NaV subtypes 1.1, 1.2, 1.3, 1.6 and 1.7. In parallel to the in vitro studies, we investigated NaV1.7 target engagement of the peptide in vivo using a rodent pain model, where m3-HwTx-IV dose-dependently suppressed spontaneous pain induced by the NaV1.7 activator OD1. Thus, our results provide further insight into the structure and dynamics of this class of peptides that may prove useful in guiding the development of inhibitors with improved selectivity for analgesic NaV subtypes.
The structure, dynamics and selectivity profile of a NaV1.7 potency-optimised huwentoxin-IV variant.,Rahnama S, Deuis JR, Cardoso FC, Ramanujam V, Lewis RJ, Rash LD, King GF, Vetter I, Mobli M PLoS One. 2017 Mar 16;12(3):e0173551. doi: 10.1371/journal.pone.0173551., eCollection 2017. PMID:28301520[11]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Peng K, Shu Q, Liu Z, Liang S. Function and solution structure of huwentoxin-IV, a potent neuronal tetrodotoxin (TTX)-sensitive sodium channel antagonist from Chinese bird spider Selenocosmia huwena. J Biol Chem. 2002 Dec 6;277(49):47564-71. Epub 2002 Sep 11. PMID:12228241 doi:10.1074/jbc.M204063200
- ↑ Xiao Y, Luo X, Kuang F, Deng M, Wang M, Zeng X, Liang S. Synthesis and characterization of huwentoxin-IV, a neurotoxin inhibiting central neuronal sodium channels. Toxicon. 2008 Feb;51(2):230-9. doi: 10.1016/j.toxicon.2007.09.008. Epub 2007 Sep , 29. PMID:18054060 doi:http://dx.doi.org/10.1016/j.toxicon.2007.09.008
- ↑ Xiao Y, Bingham JP, Zhu W, Moczydlowski E, Liang S, Cummins TR. Tarantula huwentoxin-IV inhibits neuronal sodium channels by binding to receptor site 4 and trapping the domain ii voltage sensor in the closed configuration. J Biol Chem. 2008 Oct 3;283(40):27300-13. doi: 10.1074/jbc.M708447200. Epub 2008 , Jul 14. PMID:18628201 doi:10.1074/jbc.M708447200
- ↑ Xiao Y, Blumenthal K, Jackson JO 2nd, Liang S, Cummins TR. The tarantula toxins ProTx-II and huwentoxin-IV differentially interact with human Nav1.7 voltage sensors to inhibit channel activation and inactivation. Mol Pharmacol. 2010 Dec;78(6):1124-34. doi: 10.1124/mol.110.066332. Epub 2010 Sep, 20. PMID:20855463 doi:http://dx.doi.org/10.1124/mol.110.066332
- ↑ Xiao Y, Jackson JO 2nd, Liang S, Cummins TR. Common molecular determinants of tarantula huwentoxin-IV inhibition of Na+ channel voltage sensors in domains II and IV. J Biol Chem. 2011 Aug 5;286(31):27301-10. doi: 10.1074/jbc.M111.246876. Epub 2011, Jun 9. PMID:21659528 doi:http://dx.doi.org/10.1074/jbc.M111.246876
- ↑ Revell JD, Lund PE, Linley JE, Metcalfe J, Burmeister N, Sridharan S, Jones C, Jermutus L, Bednarek MA. Potency optimization of Huwentoxin-IV on hNav1.7: a neurotoxin TTX-S sodium-channel antagonist from the venom of the Chinese bird-eating spider Selenocosmia huwena. Peptides. 2013 Jun;44:40-6. doi: 10.1016/j.peptides.2013.03.011. Epub 2013 Mar, 19. PMID:23523779 doi:http://dx.doi.org/10.1016/j.peptides.2013.03.011
- ↑ Minassian NA, Gibbs A, Shih AY, Liu Y, Neff RA, Sutton SW, Mirzadegan T, Connor J, Fellows R, Husovsky M, Nelson S, Hunter MJ, Flinspach M, Wickenden AD. Analysis of the Structural and Molecular Basis of Voltage-sensitive Sodium Channel Inhibition by the Spider Toxin Huwentoxin-IV (mu-TRTX-Hh2a). J Biol Chem. 2013 Aug 2;288(31):22707-20. doi: 10.1074/jbc.M113.461392. Epub 2013, Jun 12. PMID:23760503 doi:10.1074/jbc.M113.461392
- ↑ Murray JK, Ligutti J, Liu D, Zou A, Poppe L, Li H, Andrews KL, Moyer BD, McDonough SI, Favreau P, Stocklin R, Miranda LP. Engineering potent and selective analogues of GpTx-1, a tarantula venom peptide antagonist of the Na(V)1.7 sodium channel. J Med Chem. 2015 Mar 12;58(5):2299-314. doi: 10.1021/jm501765v. Epub 2015 Feb 19. PMID:25658507 doi:http://dx.doi.org/10.1021/jm501765v
- ↑ Agwa AJ, Lawrence N, Deplazes E, Cheneval O, Chen RM, Craik DJ, Schroeder CI, Henriques ST. Spider peptide toxin HwTx-IV engineered to bind to lipid membranes has an increased inhibitory potency at human voltage-gated sodium channel hNaV1.7. Biochim Biophys Acta. 2017 Jan 20;1859(5):835-844. doi:, 10.1016/j.bbamem.2017.01.020. PMID:28115115 doi:http://dx.doi.org/10.1016/j.bbamem.2017.01.020
- ↑ Correnti CE, Gewe MM, Mehlin C, Bandaranayake AD, Johnsen WA, Rupert PB, Brusniak MY, Clarke M, Burke SE, De Van Der Schueren W, Pilat K, Turnbaugh SM, May D, Watson A, Chan MK, Bahl CD, Olson JM, Strong RK. Screening, large-scale production and structure-based classification of cystine-dense peptides. Nat Struct Mol Biol. 2018 Mar;25(3):270-278. doi: 10.1038/s41594-018-0033-9. Epub, 2018 Feb 26. PMID:29483648 doi:http://dx.doi.org/10.1038/s41594-018-0033-9
- ↑ Rahnama S, Deuis JR, Cardoso FC, Ramanujam V, Lewis RJ, Rash LD, King GF, Vetter I, Mobli M. The structure, dynamics and selectivity profile of a NaV1.7 potency-optimised huwentoxin-IV variant. PLoS One. 2017 Mar 16;12(3):e0173551. doi: 10.1371/journal.pone.0173551., eCollection 2017. PMID:28301520 doi:http://dx.doi.org/10.1371/journal.pone.0173551
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