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).
|Number of pages||9|
|Journal||International Journal of Peptide and Protein Research|
|Publication status||Published - 1990|
- Na channel
- neurotoxic polypeptide
- physical characterization
- solid‐phase synthesis