The membranotropic activity of N-terminal peptides from the pore-forming proteins sticholysin I and II is modulated by hydrophobic and electrostatic interactions as well as lipid composition.
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Date
2011-12
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Abstract
The sea anemone Stichodactyla helianthus produces two pore-forming proteins, sticholysins I and II (St I and St II).
Despite their high identity (93%), these toxins exhibit differences in hemolytic activity that can be related to those
found in their N-terminal. To clarify the contribution of the N-terminal amino acid residues to the activity of the
toxins, we synthesized peptides spanning residues 1–31 of St I (StI1-31) or 1–30 of St II (StII1-30) and demonstrated
that StII1-30 promotes erythrocyte lysis to a higher extent than StI1-31. For a better understanding of the molecular
mechanism underlying the peptide activity, here we studied their binding to lipid monolayers and pemeabilizing
activity in liposomes. For this, we examined the effect on peptide membranotropic activity of including phospatidic
acid and cholesterol in a lipid mixture of phosphatidylcholine and sphingomyelin. The results suggest the importance
of continuity of the 1–10 hydrophobic sequence in StII1-30 for displaying higher binding and activity, in spite of both
peptides’ abilities to form pores in giant unilamellar vesicles. Thus, the different peptide membranotropic action is
explained in terms of the differences in hydrophobic and electrostatic peptide properties as well as the enhancing role
of membrane inhomogeneities.
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Keywords
Actinoporin, hemolytic peptide, permeabilizing activity, pore-forming toxin, sticholysin
Citation
Ros Uris, Pedrera Lohans, DÃaz DaylÃn, Karam Juan C De, Sudbrack Tatiane P, Valiente Pedro A, MartÃnez Diana, Cilli Eduardo M, Pazos Fabiola, Itri Rosangela, Lanio Maria E, Schreier Shirley, Ã lvarez Carlos. The membranotropic activity of N-terminal peptides from the pore-forming proteins sticholysin I and II is modulated by hydrophobic and electrostatic interactions as well as lipid composition. Journal of Biosciences. 2011 Dec; 36 (5): 781-791.