Potassium channel toxin: Difference between revisions

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New page: <StructureSection load='3odv' size='400' side='right' caption='Structure of scorpion potassium channel toxin kaliotoxin (PDB entry 3odv)' scene=''> '''Potassium channel toxins''' are...
 
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<StructureSection load='1lqh' size="350" color=""  spin="on" Scene=  caption='Scorpion potassium channel toxin, [[1lqh]]' >
__TOC__
== Function ==
'''Potassium channel toxins''' are various venoms which block the transport of potassium ions across the plasma membrane through potassium channels<ref>PMID:2181489</ref>.


<StructureSection load='3odv' size='400' side='right' caption='Structure of scorpion potassium channel toxin kaliotoxin (PDB entry [[3odv]])' scene=''>
See also [[Vm24 Scorpion Toxin]].


'''Potassium channel toxins''' are various venoms which block the transport of potassium ions across the plasma membrane through potassium channels.
==Overview==
Scorpion toxins are 61- to 76-residue long proteins that modulate the gating properties of voltage-gated sodium channels. According to their mode of action and binding properties, scorpion toxins are divided into two major classes, α- and β- toxins.
LqhαIT is a 64-residue scorpion α-toxin from [http://en.wikipedia.org/wiki/Deathstalker_scorpion Leiurus quinquestriatus hebraeus] (yellow scorpion) venom. Scorpion α-toxins prolong the action potential by inhibiting channel inactivation. The binding site of scorpion α-neurotoxins on voltage-gated sodium channels is named neurotoxin receptor site-3.
Scorpion α-toxins are similar in structure and exhibit a similar mode of action, but are very diverse in sequence and selectivity. Some scorpion α-neurotoxins show specificity for insect sodium channels and others are specific for mammalian sodium channels and exhibit different affinities to sodium channel subtypes in mammalian neurons. LqhαIT is the most insecticidal among scorpion α-toxins.


==3D structures of potassium channel toxins==
==About this Structure==
The structure of LqhαIT was solved by NMR (1) and was found to resemble that of other scorpion toxins: a core composed of an <scene name='1lqh/Helix/2'>α-helix</scene> packed against a three stranded anti-parallel <scene name='1lqh/Sheet/1'>β-sheet</scene> and stabilized by four disulfide bonds.


===Scorpion toxins===
==The Binding-Site==  
Mutational studies identified residues <scene name='1lqh/Mutations/2'>Lys8, Tyr10, Phe17, Arg18, Trp38, Asn44 and the C- tail region (Ile57, Arg58, Val59, Lys62 and Arg64)</scene> of LqhαIT as important for the interaction with sodium channels (2).
NMR studies of LqhαIT with a peptide derived from part of neurotoxin receptor site-3 (D4S3-S4) identified residues <scene name='1lqh/Nmr/1'>Lys8, Asn9, Cys12, Val13, Arg18, Trp38, Ala39 and Arg58</scene> of LqhαIT as participating in binding to that extra-cellular part of the sodium channel (3).
Both methods led to the identification of two regions on the surface of LqhαIT that participate in binding of the toxin to neurotoxin receptor site-3 on sodium channels. 


[[1pnh]] – PO5-NH2 – NMR<BR />
==3D structures of potassium channel toxins==
[[1ktx]], [[2ktx]], [[1ksw]], [[2uvs]], [[2k4u]] – kaliotoxin – NMR<BR />
[[Potassium channel toxin 3D structures]]
[[3odv]] - kaliotoxin<br />
[[1sxm]] – noxiustoxin – NMR<BR />
[[1sco]] – lenatoxin – NMR<BR />
[[1acw]] – P01 – NMR<BR />
[[1txm]] – maurotoxin – NMR<BR />
[[1tsk]] – TS kappa  – NMR<BR />
[[2pta]] – PITX-KA – NMR<BR />
[[1c49]] – PITX-KB – NMR<BR />
[[2ktc]] – BT BTK-2]] - NMR<BR />
[[1quz]], [[1wpd]], [[1y2p]] – HSTX1 – NMR<BR />
[[1wmt]] - ISTX – NMR<BR />
[[1wqc]] – OMTX1 – NMR<BR />
[[1wqe]] – OMTX3 – NMR<BR />
[[2ck4]], [[2ck5]] – OSK1 – NMR<BR />
[[2jp6]] – TC32 - NMR<BR />
[[1rji]] - BMKX – NMR<BR />
[[1big]] – BMTX1 – NMR<BR />
[[1bkt]] – BMKTX – NMR<BR />
[[1s8k]] – BMKK4]] - NMR<BR />
[[1q2k]], [[1r1g]] – BMK37 – NMR<BR />
[[3e8y ]]– BMK37<br />
[[2bmt]] – BMTX2 – NMR<BR />
[[1m2s]] – BMTX3 – NMR<BR />
[[1qky]] – PI7 – NMR<BR />
[[1n8m]] – Pi4 – NMR<BR />
[[1wz5 ]]– Pi1 – NMR<BR />
[[2k9o]] – VM24]] - NMR<BR />
[[1wm7]] - BMP01 – NMR<BR />
[[1du9 ]]– BMP02 – NMR<BR />
[[1wm8]] - BMP03 – NMR<BR />
[[1pvz]] - BMP07 – NMR<BR />
[[1j5j]], [[1lgl]] – BEKM-1 – NMR<BR />
[[2li3]] – kappa-KTX3, 1 - NMR<BR />
[[1hp9 ]]– kappa-hefutoxin 1 – NMR<BR />
[[1ne5]], [[1px9]] – ergtoxin - NMR<BR />
[[1hp2]] – tityustoxin K alpha – NMR<BR />
[[1jlz]] - tityustoxin alpha KTX – NMR<BR />
[[1scy]] – scyllatoxin – NMR<BR />
[[1hly]] – hongotoxin]] - NMR<BR />
[[1c55]], [[1c56]], [[1wt7]] – butantoxin – NMR<BR />
[[2axx]] – discrepin]] - NMR<BR />
[[1agt]] – agitoxin – NMR<BR />
[[1v56]] – spinoxin]] - NMR<BR />
[[1pjv]] – cobatoxin]] - NMR<BR />
[[1mtx]]– margatoxin – NMR<BR />
[[2kfe]] – meucin-24 – NMR<BR />
[[2ky3]] – tamapin]] - NMR<BR />


===Sea anemone toxins===
</StructureSection>


[[1bgk ]]– BGK – NMR<BR />
== References ==
[[1roo]] – SHK – NMR<BR />
<references/>
[[2k9e]] – SHK (mutant)]] - NMR<BR />
[[Category:Topic Page]]
[[1bei]], [[1c2u]] – SHK (mutant)]] - NMR<BR />
 
</StructureSection>

Latest revision as of 13:51, 26 January 2022

Function

Potassium channel toxins are various venoms which block the transport of potassium ions across the plasma membrane through potassium channels[1].

See also Vm24 Scorpion Toxin.

Overview

Scorpion toxins are 61- to 76-residue long proteins that modulate the gating properties of voltage-gated sodium channels. According to their mode of action and binding properties, scorpion toxins are divided into two major classes, α- and β- toxins.

LqhαIT is a 64-residue scorpion α-toxin from Leiurus quinquestriatus hebraeus (yellow scorpion) venom. Scorpion α-toxins prolong the action potential by inhibiting channel inactivation. The binding site of scorpion α-neurotoxins on voltage-gated sodium channels is named neurotoxin receptor site-3.

Scorpion α-toxins are similar in structure and exhibit a similar mode of action, but are very diverse in sequence and selectivity. Some scorpion α-neurotoxins show specificity for insect sodium channels and others are specific for mammalian sodium channels and exhibit different affinities to sodium channel subtypes in mammalian neurons. LqhαIT is the most insecticidal among scorpion α-toxins.

About this Structure

The structure of LqhαIT was solved by NMR (1) and was found to resemble that of other scorpion toxins: a core composed of an packed against a three stranded anti-parallel and stabilized by four disulfide bonds.

The Binding-Site

Mutational studies identified residues of LqhαIT as important for the interaction with sodium channels (2).

NMR studies of LqhαIT with a peptide derived from part of neurotoxin receptor site-3 (D4S3-S4) identified residues of LqhαIT as participating in binding to that extra-cellular part of the sodium channel (3). Both methods led to the identification of two regions on the surface of LqhαIT that participate in binding of the toxin to neurotoxin receptor site-3 on sodium channels.

3D structures of potassium channel toxins

Potassium channel toxin 3D structures


PDB ID 1lqh

Drag the structure with the mouse to rotate

ReferencesReferences

  1. ↑ Strong PN. Potassium channel toxins. Pharmacol Ther. 1990;46(1):137-62. PMID:2181489

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Michal Harel
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