Etude des interactions proteine-lipide: Contribution a l'etude du mecanisme d'action de la pediocine PA-1

Pediocin PA-1 is an antimicrobial peptide that should induce the cell-death by (1) electrostatic interaction between its N-terminal part and the membrane of target cell; (2) insertion of the C-terminal part in the bilayer and (3) a pore formation. In order to contribute to this study, we have developed a new purification procedure using HCl instead of TFA. Indeed, TFA was seen to be a purification contaminant that affects the structure of protein. FTIR studies revealed that active pediocin is unfolded in aqueous medium. The decrease of the activity is relied to an increase of the folding and an irreversible thermal aggregation. Pediocin PA-1 interacts with anionic phospholipid (DMPG) with its N-terminal part. This interaction induces the folding of the peptide and affects the interfacial region of the DMPG. There is no effect on the hydrophobic core. The cell death may be the result of the destabilization of the lipid packing.