TY - JOUR
T1 - Mollusc‐specific toxins from the venom of Conus textile neovicarius
AU - FAINZILBER, Michael
AU - GORDON, Dalia
AU - HASSON, Arik
AU - SPIRA, Micha E.
AU - ZLOTKIN, Eliahu
PY - 1991/12
Y1 - 1991/12
N2 - Three peptide toxins exhibiting strong paralytic activity to molluscs, but with no paralytic effects on arthropods or vertebrates, were purified from the venom of the molluscivorous snail Conus textile neovicarius from the Red Sea. The amino acid sequences of these mollusc specific toxins are: TxIA, WCKQSGEMCNLLDQNCCDGYCIVLVCT (identical to the so called ‘King Kong peptide’); TxIB, WCKQSGEMCNVLDQNCCDGYCIVFVCT; TxIIA, WGGYSTYCγVDSγCCSDNCVRSYCT (γ=γ‐carboxyglutamate). There is a similarity of the Cys framework of these toxins to that of the ω‐conotoxins; however, their net negative charges, high content of hydrophobic residues and uneven number of Cys residues in TxIIA, are highly unusual for conotoxins. When assayed on isolated cultured Aplysia neurons, all three toxins induced membrane depolarization and spontaneous repetitive firing. The TxI toxins also induce a marked prolongation of the action potential duration, which is sodium dependent. These effects differ significantly from the blocking activities of piscivorous venom conotoxins. These mollusc specific conotoxins may therefore serve as new and selective probes for ion‐channel functions in molluscan neuronal systems.
AB - Three peptide toxins exhibiting strong paralytic activity to molluscs, but with no paralytic effects on arthropods or vertebrates, were purified from the venom of the molluscivorous snail Conus textile neovicarius from the Red Sea. The amino acid sequences of these mollusc specific toxins are: TxIA, WCKQSGEMCNLLDQNCCDGYCIVLVCT (identical to the so called ‘King Kong peptide’); TxIB, WCKQSGEMCNVLDQNCCDGYCIVFVCT; TxIIA, WGGYSTYCγVDSγCCSDNCVRSYCT (γ=γ‐carboxyglutamate). There is a similarity of the Cys framework of these toxins to that of the ω‐conotoxins; however, their net negative charges, high content of hydrophobic residues and uneven number of Cys residues in TxIIA, are highly unusual for conotoxins. When assayed on isolated cultured Aplysia neurons, all three toxins induced membrane depolarization and spontaneous repetitive firing. The TxI toxins also induce a marked prolongation of the action potential duration, which is sodium dependent. These effects differ significantly from the blocking activities of piscivorous venom conotoxins. These mollusc specific conotoxins may therefore serve as new and selective probes for ion‐channel functions in molluscan neuronal systems.
UR - http://www.scopus.com/inward/record.url?scp=0025932018&partnerID=8YFLogxK
U2 - 10.1111/j.1432-1033.1991.tb16412.x
DO - 10.1111/j.1432-1033.1991.tb16412.x
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C2 - 1761058
AN - SCOPUS:0025932018
SN - 0014-2956
VL - 202
SP - 589
EP - 595
JO - European Journal of Biochemistry
JF - European Journal of Biochemistry
IS - 2
ER -