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Screening and cDNA cloning of Kv1 potassium channel toxins in sea anemones.

Yamaguchi Y, Hasegawa Y, Honma T, Nagashima Y, Shiomi K - Mar Drugs (2010)

Bottom Line: When 21 species of sea anemones were screened for Kv1 potassium channel toxins by competitive inhibition of the binding of (125)I-α-dendrotoxin to rat synaptosomal membranes, 11 species (two species of Actiniidae, one species of Hormathiidae, five species of Stichodactylidae and three species of Thalassianthidae) were found to be positive.The precursors of these six toxins are commonly composed of signal peptide, propart and mature peptide portions.As for the mature peptide (35 amino acid residues), the six toxins share more than 90% sequence identities with one another and with κ(1.3)-SHTX-She1a (Shk) from Stichodactyla helianthus but only 34-63% identities with the other type 1 potassium channel toxins.

View Article: PubMed Central - PubMed

Affiliation: Department of Food Science and Technology, Tokyo University of Marine Science and Technology, Konan-4, Minato-ku, Tokyo, Japan.

ABSTRACT
When 21 species of sea anemones were screened for Kv1 potassium channel toxins by competitive inhibition of the binding of (125)I-α-dendrotoxin to rat synaptosomal membranes, 11 species (two species of Actiniidae, one species of Hormathiidae, five species of Stichodactylidae and three species of Thalassianthidae) were found to be positive. Furthermore, full-length cDNAs encoding type 1 potassium channel toxins from three species of Stichodactylidae and three species of Thalassianthidae were cloned by a combination of RT-PCR, 3'RACE and 5'RACE. The precursors of these six toxins are commonly composed of signal peptide, propart and mature peptide portions. As for the mature peptide (35 amino acid residues), the six toxins share more than 90% sequence identities with one another and with κ(1.3)-SHTX-She1a (Shk) from Stichodactyla helianthus but only 34-63% identities with the other type 1 potassium channel toxins.

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Inhibition of the binding of 125I-α-dendrotoxin to rat synaptosomal membranes by crude extracts from 21 species of sea anemones. Each datum is a mean of two determinations.
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f1-marinedrugs-08-02893: Inhibition of the binding of 125I-α-dendrotoxin to rat synaptosomal membranes by crude extracts from 21 species of sea anemones. Each datum is a mean of two determinations.

Mentions: Crude extracts from 21 species of sea anemones were examined for Kv1 potassium channel toxicity by competitive inhibition experiments. As shown in Figure 1, inhibition of the binding of 125I-α-dendrotoxin to rat synaptosomal membranes was observed in all species with varied potencies. The species with only weak inhibitory activity were considered to be hardly selected as samples in future study on potassium channel toxins. In this study, therefore, the following 11 species showing more than 50% inhibition were judged to be substantially positive: two species (Macrodactyla doreensis and Telactinia citrina) of the family Actiniidae, one species (Calliactis polypus) of the family Hormathiidae, five species (Heteractis magnifica, Mesactinia ganensis, Stichodactyla haddoni, Stichodactyla mertensii and Stichodactyla tapetum) of the family Stichodactylidae and three species (Cryptodendrum adhaesivum, Heterodactyla hemprichii and Thalassianthus aster) of the family Thalassianthidae. One Kv1 potassium channel toxin (κ1.3-SHTX-Hm1a) has already been isolated from H. magnifica [15] and three Kv1 potassium channel toxins (κ1.3-SHTX-Sha2a, κ1.3-SHTX-Sha3a and κ1.3-SHTX-Sha3b) from S. haddoni [17]. Furthermore, previous screening has established the occurrence of Kv1 potassium channel toxins in S. mertensii [21]. The remaining eight species were first demonstrated to be positive in this study. So far, Kv1 potassium channel toxins have not been found in any species other than those belonging to the family Actiniidae or Stichodactylidae. In view of this, our screening data are of particular value in showing the occurrence of Kv1 potassium channel toxins in one species of Hormathiidae and three species of Thalassianthidae.


Screening and cDNA cloning of Kv1 potassium channel toxins in sea anemones.

Yamaguchi Y, Hasegawa Y, Honma T, Nagashima Y, Shiomi K - Mar Drugs (2010)

Inhibition of the binding of 125I-α-dendrotoxin to rat synaptosomal membranes by crude extracts from 21 species of sea anemones. Each datum is a mean of two determinations.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC3039155&req=5

f1-marinedrugs-08-02893: Inhibition of the binding of 125I-α-dendrotoxin to rat synaptosomal membranes by crude extracts from 21 species of sea anemones. Each datum is a mean of two determinations.
Mentions: Crude extracts from 21 species of sea anemones were examined for Kv1 potassium channel toxicity by competitive inhibition experiments. As shown in Figure 1, inhibition of the binding of 125I-α-dendrotoxin to rat synaptosomal membranes was observed in all species with varied potencies. The species with only weak inhibitory activity were considered to be hardly selected as samples in future study on potassium channel toxins. In this study, therefore, the following 11 species showing more than 50% inhibition were judged to be substantially positive: two species (Macrodactyla doreensis and Telactinia citrina) of the family Actiniidae, one species (Calliactis polypus) of the family Hormathiidae, five species (Heteractis magnifica, Mesactinia ganensis, Stichodactyla haddoni, Stichodactyla mertensii and Stichodactyla tapetum) of the family Stichodactylidae and three species (Cryptodendrum adhaesivum, Heterodactyla hemprichii and Thalassianthus aster) of the family Thalassianthidae. One Kv1 potassium channel toxin (κ1.3-SHTX-Hm1a) has already been isolated from H. magnifica [15] and three Kv1 potassium channel toxins (κ1.3-SHTX-Sha2a, κ1.3-SHTX-Sha3a and κ1.3-SHTX-Sha3b) from S. haddoni [17]. Furthermore, previous screening has established the occurrence of Kv1 potassium channel toxins in S. mertensii [21]. The remaining eight species were first demonstrated to be positive in this study. So far, Kv1 potassium channel toxins have not been found in any species other than those belonging to the family Actiniidae or Stichodactylidae. In view of this, our screening data are of particular value in showing the occurrence of Kv1 potassium channel toxins in one species of Hormathiidae and three species of Thalassianthidae.

Bottom Line: When 21 species of sea anemones were screened for Kv1 potassium channel toxins by competitive inhibition of the binding of (125)I-α-dendrotoxin to rat synaptosomal membranes, 11 species (two species of Actiniidae, one species of Hormathiidae, five species of Stichodactylidae and three species of Thalassianthidae) were found to be positive.The precursors of these six toxins are commonly composed of signal peptide, propart and mature peptide portions.As for the mature peptide (35 amino acid residues), the six toxins share more than 90% sequence identities with one another and with κ(1.3)-SHTX-She1a (Shk) from Stichodactyla helianthus but only 34-63% identities with the other type 1 potassium channel toxins.

View Article: PubMed Central - PubMed

Affiliation: Department of Food Science and Technology, Tokyo University of Marine Science and Technology, Konan-4, Minato-ku, Tokyo, Japan.

ABSTRACT
When 21 species of sea anemones were screened for Kv1 potassium channel toxins by competitive inhibition of the binding of (125)I-α-dendrotoxin to rat synaptosomal membranes, 11 species (two species of Actiniidae, one species of Hormathiidae, five species of Stichodactylidae and three species of Thalassianthidae) were found to be positive. Furthermore, full-length cDNAs encoding type 1 potassium channel toxins from three species of Stichodactylidae and three species of Thalassianthidae were cloned by a combination of RT-PCR, 3'RACE and 5'RACE. The precursors of these six toxins are commonly composed of signal peptide, propart and mature peptide portions. As for the mature peptide (35 amino acid residues), the six toxins share more than 90% sequence identities with one another and with κ(1.3)-SHTX-She1a (Shk) from Stichodactyla helianthus but only 34-63% identities with the other type 1 potassium channel toxins.

Show MeSH