INFLUENCE OF THE MODE OF INSERTION OF SIV PEPTIDES INTO MEMBRANES ON THE STRUCTURE OF MODEL MEMBRANE AS STUDIED BY P-31 NMR

The influence on model membrane organization of a fusion peptide of SI V and of a nonfusogenic mutant of this peptide was examined by molecul ar modeling and by P-31 NMR, The calculated mode of insertion of the f usion peptide shows that it adopts an oblique orientation towards the lipid-water interface and that this fusion peptide induces a destabili zation of the bilayer structure of multilamellar vesicles as evidenced by 31P NMR observations. The SIV mutant showing a more vertical inser tion into lipid layers is unable to induce nonlamellar structures. Thi s study reinforces the correlation between fusogenic activity, inducti on of structures not organized in extended bilayers, and calculated mo de of insertion of peptides into lipid layers. (C) 1998 Academic Press .