The role of tryptophan in structural and functional properties of equinatoxin II.

摘要: A pore-forming, cytolytic and lethal polypeptide, equinatoxin II, from the sea anemone Actinia equina , was subjected to oxidation with N -bromosuccinimide study role of five present tryptophan residues in structure-function relationships. In folded toxin molecule, 1–2 were readily susceptible -bromosuccinimide, whereas modification a single residue resulted complete impairment hemolytic activities as well ability an oxidized precipitate serum lipoproteins. CD fluorescence spectra indicated slight alteration secondary structure following treatment. Incubation sphingomyelin prior did not prevent subsequent loss its activities, indicating that modified is directly involved binding insertion into lipid membranes. It concluded essential for II.