DESTABILIZATION OF A MODEL MEMBRANE BY A PREDICTED FUSION PEPTIDE OF FERTILIN-ALPHA

The subunit alpha of the guinea pig fertilin (previously known as PH-3 0, an integral membrane protein involved in sperm-egg binding and fusi on) is predicted to be a potential fusion protein. The structure of th is putative fusion protein was analysed by molecular modeling and we h ave found a peptidic sequence of 17 residues (D-83-P-99) organized in helix that inserts obliquely in lipid phases. The effect of this synth esized peptide was studied on a model membrane by P-31 NMR and light s cattering, It appears to increase the size of lipid vesicles and induc es structural modifications. We interpret these observations as a dest abilization of the lipid organization by this peptide because of its t ilted insertion in phospholipid layers. This destabilization could fav or membrane fusion.