Potassium channel toxin
From Proteopedia
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| - | <StructureSection load=' | + | <StructureSection load='1lqh' size="400" color="" spin="on" Scene= caption='Scorpion toxin, [[1lqh]]' > |
'''Potassium channel toxins''' are various venoms which block the transport of potassium ions across the plasma membrane through potassium channels. | '''Potassium channel toxins''' are various venoms which block the transport of potassium ions across the plasma membrane through potassium channels. | ||
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| + | ==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, alpha- and beta- 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. | ||
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| + | 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. | ||
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| + | ==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. | ||
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| + | ==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. | ||
| + | </StructureSection> | ||
==3D structures of potassium channel toxins== | ==3D structures of potassium channel toxins== | ||
Revision as of 09:18, 20 August 2014
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3D structures of potassium channel toxins
Updated on 20-August-2014
Scorpion toxins
1pnh – PO5-NH2 – NMR
1ktx, 2ktx, 1ksw, 2uvs, 2k4u – kaliotoxin – NMR
3odv - kaliotoxin
1sxm – noxiustoxin – NMR
1sco – lenatoxin – NMR
1acw – P01 – NMR
1txm – maurotoxin – NMR
1tsk – TS kappa – NMR
2pta – PITX-KA – NMR
1c49 – PITX-KB – NMR
2ktc – BT BTK-2 - NMR
1quz, 1wpd, 1y2p – HSTX1 – NMR
1wmt - ISTX – NMR
1wqc – OMTX1 – NMR
1wqe – OMTX3 – NMR
2ck4, 2ck5 – OSK1 – NMR
2jp6 – TC32 - NMR
1rji - BMKX – NMR
1big – BMTX1 – NMR
1bkt – BMKTX – NMR
1s8k – BMKK4 - NMR
1q2k, 1r1g – BMK37 – NMR
3e8y – BMK37
2bmt – BMTX2 – NMR
1m2s – BMTX3 – NMR
1qky – PI7 – NMR
1n8m – Pi4 – NMR
1wz5 – Pi1 – NMR
2k9o – VM24 - NMR
1wm7 - BMP01 – NMR
1du9 – BMP02 – NMR
1wm8 - BMP03 – NMR
1pvz - BMP07 – NMR
1j5j, 1lgl – BEKM-1 – NMR
2li3 – kappa-KTX3, 1 - NMR
1hp9 – kappa-hefutoxin 1 – NMR
1ne5, 1px9 – ergtoxin - NMR
1hp2 – tityustoxin K alpha – NMR
1jlz - tityustoxin alpha KTX – NMR
1scy – scyllatoxin – NMR
1hly – hongotoxin - NMR
1c55, 1c56, 1wt7 – butantoxin – NMR
2axx – discrepin - NMR
1agt – agitoxin – NMR
1v56 – spinoxin - NMR
1pjv – cobatoxin - NMR
1mtx– margatoxin – NMR
2kfe – meucin-24 – NMR
2ky3, 2lu9 – tamapin - NMR
1bah, 2crd – charybdotoxin - NMR
1cmr – charybdotoxin (mutant) - NMR
4jta, 4jtc, 4jtd – charybdotoxin + voltage-gated potassium channel β2
2sn3 – toxin – Centruroides exilicauda
1ptx – toxin – Androctonus australis
1lqh, 1lqi – toxin α – Leiurus quinquestriatus hebraeus – NMR
1snb – MmBMK M8 – Mesobuthus martensii
1sn1 - MmBMK M1
Sea anemone toxins
1bgk – BGK – NMR
1roo – SHK – NMR
2k9e – SHK (mutant) - NMR
1bei, 1c2u – SHK (mutant) - NMR
4lfq, 4lfs – SHK
</StructureSection>
