Identification and characterization of novel sodium channel toxins from the sea anemone Anthopleura xanthogrammica

• Published in: Toxicon (Oxford) 1998, Vol.36 (1), p.41-51
• Main Authors: Kelso, Gregory J., Blumenthal, Kenneth M.
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Animal poisons toxicology. Antivenoms; Animals; Anthopleura xanthogrammica; Biological and medical sciences; Cnidarian Venoms - analysis; Cysteine - chemistry; Medical sciences; Mice; Molecular Sequence Data; Rats; Sea Anemones - chemistry; Sodium Channels - drug effects; Toxicology; Tumor Cells, Cultured
• ISSN: 0041-0101; 1879-3150
• DOI: 10.1016/S0041-0101(97)00064-0

Six new toxins from the sea anemone Anthopleura xanthogrammica were identified using a molecular biological approach. Five of these novel isoforms resemble the 47 residue type I long polypeptides native to Anthopleura elegantissima, Anthopleura fuscoviridis and Anemonia sulcata, while one appears to be a chimera of the two previously identified 49 residue toxins native to A. xanthogrammica. Four of these toxins were expressed in bacteria, purified and characterized by ion flux assays in RT4-B and N1E-115 cell lines expressing the cardiac and neuronal Na channel isoforms, respectively. The novel 47 residue toxin isoforms form a new subclass within the A. xanthogrammica neurotoxin family, although they are related to previously described anemone toxins. One of the three 47 residue toxins characterized, PCR2-10, enhances veratridine-dependent sodium uptake, displaying a K 0.5 of 329 nM and 1354 nM in RT4-B and N1E-115 cell lines, respectively. The novel 49 residue toxin, PCR3-7, interacts with the sodium channel with even higher affinity, enhancing sodium uptake with a K 0.5 of 47 nM and 108 nM in RT4-B and N1E-115 cells, respectively.