Chemical synthesis of a neurotoxic polypeptide from the sea anemone Stichodactyla helianthus

Michael W. Pennington, William R. Kem, Raymond S. Norton, Ben M. Dunn

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The sea anemone Stichodactyla helianthus neurotoxin I, a 48‐residue polypeptide, was synthesized by automated solid phase methodology. The fully reduced polypeptide was subsequently refolded in the presence of a glutathione oxidoreduction buffer to the biologically active species containing three disulfide bonds. The overall yield after rigorous purification was 12.5%. The circular dichroism (CD), and proton nuclear magnetic resonance (1 H NMR) spectra of the HPLC‐purified synthetic toxin were indistinguishable from those obtained concurrently with the natural toxin. A subtilisin digest of the synthetic neurotoxin generated peptide fragments identical to that of a sample of the natural toxin subjected to the same treatment. The toxicity of the synthetic polypeptide was identical to that of the natural toxin (crab LD50, 3.1μg/kg). The equilibrium dissociation constant (28 nM) for interaction of the synthetic toxin with crab axolemma vesicles was nearly identical to that of the natural toxin (25 nM).

Original languageEnglish
Pages (from-to)335-343
Number of pages9
JournalInternational Journal of Peptide and Protein Research
Issue number4
Publication statusPublished - 1990
Externally publishedYes


  • Na channel
  • neurotoxic polypeptide
  • physical characterization
  • solid‐phase synthesis

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