Novel peptide toxins from acrorhagi, aggressive organs of the sea anemone Actinia equina.
Two peptide toxins, acrorhagin I (50 residues) and II (44 residues), were isolated from special aggressive organs (acrorhagi) of the sea anemone Actinia equina by gel filtration on Sephadex G-50 and reverse-phase HPLC on TSKgel ODS-120T. The LD50 against crabs of acrorhagin I and II were estimated to be 520 and 80 microg/kg, respectively. 3'- and 5'-RACE established the amino acid sequences of the acrorhagin precursors. The precursor of acrorhagin I is composed of both signal and mature peptides and that of acrorhagin II has an additional sequence (propart) between signal and mature peptides. Acrorhagin I has no sequence homologies with any toxins, while acrorhagin II is somewhat similar to spider neurotoxins (hainantoxin-I from Selenocosmia hainana and Tx 3-2 from Phoneutria nigriventer) and cone snail neurotoxin (omega-conotoxin MVIIB from Conus magus). In addition, analogous peptides (acrorhagin Ia and IIa) were also cloned during RT-PCR experiments performed to confirm the nucleotide sequences of acrorhagins. This is the first to demonstrate the existence of novel peptide toxins in the sea anemone acrorhagi.
Honma
Tomohiro
T
Department of Food Science and Technology, Tokyo University of Marine Science and Technology, Konan-4, Minato-ku, Tokyo 108-8477, Japan.
Minagawa
Sonomi
S
Nagai
Hiroshi
H
Ishida
Masami
M
Nagashima
Yuji
Y
Shiomi
Kazuo
K
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003064:Cnidarian Venoms / Q000737:chemistry* / Q000235:genetics; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics; D008387:Marine Toxins / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification* / Q000633:toxicity; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000633:toxicity*; D012615:Sea Anemones / Q000033:anatomy & histology* / Q000737:chemistry*; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
D003064:Cnidarian Venoms; D018076:DNA, Complementary; D008387:Marine Toxins; D010455:Peptides