title: 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.
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.
authors: Center for Protein Studies, Biology Faculty, University of Havana, Havana, Cuba.
authors: Uris
authors: U
authors: Ros
authors: Lohans
authors: L
authors: Pedrera
authors: DaylÍn
authors: D
authors: Diaz
authors: Juan C De
authors: JC
authors: Karam
authors: Tatiane P
authors: TP
authors: Sudbrack
authors: Pedro A
authors: PA
authors: Valiente
authors: Diana
authors: D
authors: MartÍnez
authors: Eduardo M
authors: EM
authors: Cilli
authors: Fabiola
authors: F
authors: Pazos
authors: Rosangela
authors: R
authors: Itri
authors: Maria E
authors: ME
authors: Lanio
authors: Shirley
authors: S
authors: Schreier
authors: Carlos
authors: C
authors: Ávarez
mesh_terms: D000595:Amino Acid Sequence; D003064:Cnidarian Venoms / Q000138:chemical synthesis / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D008051:Lipid Bilayers / Q000737:chemistry*; D008563:Membrane Lipids / Q000737:chemistry*; D008969:Molecular Sequence Data; D009930:Organic Chemicals / Q000138:chemical synthesis / Q000737:chemistry; D010446:Peptide Fragments / Q000138:chemical synthesis / Q000737:chemistry*; D010539:Permeability; D011485:Protein Binding; D053835:Unilamellar Liposomes / Q000737:chemistry
chemical_list: D003064:Cnidarian Venoms; D008051:Lipid Bilayers; D008563:Membrane Lipids; D009930:Organic Chemicals; D010446:Peptide Fragments; D053835:Unilamellar Liposomes; C404794:sticholysin II; C121348:stycholysin I