View source for 5tlr


==Solution NMR structure of gHwTx-IV==
<StructureSection load='5tlr' size='340' side='right'caption='[[5tlr]]' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[5tlr]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Cyriopagopus_schmidti Cyriopagopus schmidti]. Full experimental information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=5TLR OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=5TLR FirstGlance]. <br>
</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=NH2:AMINO+GROUP'>NH2</scene></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=5tlr FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=5tlr OCA], [https://pdbe.org/5tlr PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=5tlr RCSB], [https://www.ebi.ac.uk/pdbsum/5tlr PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=5tlr ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/TXH4_CYRSC 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).<ref>PMID:12228241</ref> <ref>PMID:18054060</ref> <ref>PMID:18628201</ref> <ref>PMID:20855463</ref> <ref>PMID:21659528</ref> <ref>PMID:23523779</ref> <ref>PMID:23760503</ref> <ref>PMID:25658507</ref> <ref>PMID:28115115</ref> <ref>PMID:29483648</ref> 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
The human voltage-gated sodium channel sub-type 1.7 (hNaV1.7) is emerging as an attractive target for the development of potent and sub-type selective novel analgesics with increased potency and fewer side effects than existing therapeutics. HwTx-IV, a spider derived peptide toxin, inhibits hNaV1.7 with high potency and is therefore of great interest as an analgesic lead. In the current study we examined whether engineering a HwTx-IV analogue with increased ability to bind to lipid membranes would improve its inhibitory potency at hNaV1.7. This hypothesis was explored by comparing HwTx-IV and two analogues [E1PyrE]HwTx-IV (mHwTx-IV) and [E1G,E4G,F6W,Y30W]HwTx-IV (gHwTx-IV) on their membrane-binding affinity and hNaV1.7 inhibitory potency using a range of biophysical techniques including computational analysis, NMR spectroscopy, surface plasmon resonance, and fluorescence spectroscopy. HwTx-IV and mHwTx-IV exhibited weak affinity for lipid membranes, whereas gHwTx-IV showed improved affinity for the model membranes studied. In addition, activity assays using SH-SY5Y neuroblastoma cells expressing hNaV1.7 showed that gHwTx-IV has increased activity at hNaV1.7 compared to HwTx-IV. Based on these results we hypothesize that an increase in the affinity of HwTx-IV for lipid membranes is accompanied by improved inhibitory potency at hNaV1.7 and that increasing the affinity of gating modifier toxins to lipid bilayers is a strategy that may be useful for improving their potency at hNaV1.7.

Spider peptide toxin HwTx-IV engineered to bind to lipid membranes has an increased inhibitory potency at human voltage-gated sodium channel hNaV1.7.,Agwa AJ, Lawrence N, Deplazes E, Cheneval O, Chen RM, Craik DJ, Schroeder CI, Henriques ST Biochim Biophys Acta. 2017 Jan 20;1859(5):835-844. doi:, 10.1016/j.bbamem.2017.01.020. PMID:28115115<ref>PMID:28115115</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 5tlr" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Cyriopagopus schmidti]]
[[Category: Large Structures]]
[[Category: Agwa AJ]]
[[Category: Schroeder CI]]