P-47 Aculeineおよびその類縁体の構造解析(ポスター発表の部)

抄録

Aculeines (ACUs) are new peptide toxins isolated from the marine sponge A. aculeata collected at Iriomote, Okinawa. ACUs exhibited neurotoxicity through disrupting cell membrane and inducing robust influx of Ca^<2+> ions. ACUs are modified by long-chain polyamines (LCPAs) at the Nterminal amino acid. Amino acid sequence of the peptide portion of ACU-A was determined on the basis of Edman degradation, nucleotide sequence analysis, and peptide-mass mapping to be a 44-amino acid polypeptide. The peptide-mass mapping for ACU-B showed that it shares the same peptide portion with ACU-A. The nucleotide sequence analysis suggested that the Nterminal of ACU-A/B to be Trp, however; their structures were difficult to be elucidated because of a minute amount of peptides available and highly unusual modification by LCPA. In the present study, we isolated Nterminal fragments E and E' obtained from enzyme digest of ACU-A and B, respectively. We also found a novel LCPA derivative protoaculaine (1) that possibly represents the structures of the Nterminal portion of ACUs form the aqueous extract. Here we report the structure elucidation of those compounds.