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The toxin consists of 31 amino acids (ACSRAGENCYKSGRCCDGLYCKAYVVTCYKP). This sequence forms a peptide with a molecular weight of 3.4 kDa. It has six cysteine residues which form three disulphide bonds, between the specific amino acid locations 2&16, 19&21 and 15&28. There is an equal
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Experiments have shown that these symptoms are not in present in cockroaches or mice after Cvtx-II injections. Therefore, Cvtx-II is thought to be an insect species-specific neurotoxic peptide. A dose of 0.2 μmol/g was necessary to immobilize or inactivate 50% of the insects
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Balaji RA, Sasaki T, Gopalakrishnakone P, Sato K, Kini RM, Bay BH (2000). "Purification, structure determination and synthesis of covalitoxin-II, a short insect-specific neurotoxic peptide from the venom of the
Coremiocnemis validus (Singapore tarantula)".
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distribution of hydrophilic, hydrophobic and neutral amino acids. Near the C-terminus there is a positively charged surface formed by conserved basic residues, which is thought to interact with an ion channel. The
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The specific target and mechanism of action of Cvtx-II are not yet clear. Based on its effect on behavior, it has been speculated that Cvtx-II targets sodium channel inactivation, analogous to some excitotoxins.
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UniProt, UniProt
Knowledge Base; P82601 (TXVL2_CORVA); published December 1, 2000; Last modified October 3, 2012; Date of retrieval October 16, 2012;
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motif that is formed by the cysteine residues shows analogy to other spider toxins and can also be found in ω-
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23:. It can induce excitatory, non-lethal behavioral symptoms like quivering and jerking in crickets.
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Grishin E; Polypeptide neurotoxins from spider venoms; Eur. J. Biochem. 1999 Sep;264(2):276-80.
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Grishin, E. (1999). "Polypeptide neurotoxins from spider venoms".
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47% homology with spider peptide PLTX-II (calcium channel blocker)
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Cvtx-II induces the following non-lethal symptoms in crickets:
128:). After 40–60 minutes, the immobilizing effects disappear.
39:). This spider lives in South East Asian tropical forests.
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Covalitoxin-II (Cvtx-II) is a toxin in the venom of
98:Quivering, jerking, and hyperextension of the legs
19:is a peptide toxin that is produced by the spider
101:Rapid movement of antenna, mandibles and maxillae
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61:, which are present in the venom of
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235:10.1046/j.1432-1327.1999.00622.x
223:European Journal of Biochemistry
76:MrVIB (sodium channel blocker)
81:Target and mechanism of action
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179:10.1016/s0014-5793(00)01593-3
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116:Greatly reduced locomotion
35:(Singapore or Blue femur
119:Indications of paralysis
55:inhibitor cystine knot
107:Frequent body arching
104:Abdominal contraction
33:Coremiocnemis validus
21:Coremiocnemis validus
171:2000FEBSL.474..208B
72:47% homology with
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159:FEBS Lett
74:conotoxin
48:Structure
43:Chemistry
37:tarantula
257:Category
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187:10838086
110:Loss of
90:Toxicity
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