An epidermal growth factor-like toxin and two sodium channel toxins from the sea anemone Stichodactyla gigantea.
Three peptide toxins (gigantoxins I-III) with crab toxicity were isolated from the sea anemone Stichodactyla gigantea by gel filtration on Sephadex G-50 and reverse-phase HPLC on TSKgel ODS-120T and their complete amino acid sequences were determined. Gigantoxins II (44 residues) and III (48 residues) have LD(50) (against crabs) of 70 and 120 microg/kg, respectively, and are analogous to the known type 1 and 2 sea anemone sodium channel toxins, respectively. On the other hand, gigantoxin I (48 residues) is potently paralytic to crabs (ED(50) 215 microg/kg), although its lethality is very weak (LD(50)>1000 microg/kg). Interestingly, gigantoxin I has 31-33% homologies with mammalian epidermal growth factors (EGFs), with the same location of six cysteine residues. In accordance with the sequence similarity, gigantoxin I exhibits EGF activity as evidenced by rounding of A431 cells and tyrosine phosphorylation of the EGF receptor in the cells, although much less potently than human EGF. Gigantoxin I is the first example of EGF-like toxins of natural origin.
Shiomi
Kazuo
K
Department of Food Science and Technology, Tokyo University of Fisheries, Konan-4, Minato-ku, 108-8477, Tokyo, Japan. shiomi@tokyo-u-fish.ac.jp
Honma
Tomohiro
T
Ide
Masao
M
Nagashima
Yuji
Y
Ishida
Masami
M
Chino
Makoto
M
D000595:Amino Acid Sequence; D000818:Animals; D003064:Cnidarian Venoms / Q000737:chemistry / Q000302:isolation & purification* / Q000633:toxicity; D004815:Epidermal Growth Factor / Q000737:chemistry / Q000633:toxicity; D007928:Lethal Dose 50; D008387:Marine Toxins / Q000737:chemistry / Q000302:isolation & purification*; D051379:Mice; D008969:Molecular Sequence Data; D010243:Paralysis / Q000139:chemically induced; D010455:Peptides / Q000737:chemistry / Q000302:isolation & purification* / Q000633:toxicity; D012615:Sea Anemones / Q000502:physiology*; D016415:Sequence Alignment; D015222:Sodium Channels / Q000737:chemistry; D014407:Tumor Cells, Cultured
D003064:Cnidarian Venoms; D008387:Marine Toxins; D010455:Peptides; D015222:Sodium Channels; D004815:Epidermal Growth Factor