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Étude des mécanismes de perturbation membranaire de peptides amphiphiles par spectroscopies de RMN à l'état solide et infrarouge
| Content Provider | Semantic Scholar |
|---|---|
| Author | Ouellet, Marise |
| Copyright Year | 2007 |
| Abstract | This thesis is related to the détermination of the membrane perturbation mechanisms of 14 and 21 amino acid amphipathic synthetic peptides by solid-state NMR and infrared spectroscopies. Previous studies hâve shown that the 14and 21-mer peptides exhibit membrane activities similar to those observed for natural antimicrobial peptides and their related analogues. To better understand the type of interactions that are involved in the modes of membrane perturbation of the 14and 21 -mer peptides, and then to plan the design and synthesis of synthetic peptides with sélective antimicrobial activity, we hâve studied the interaction between the peptides and a variety of model membranes. The types of model membranes used in thèse studies are zwitterionic and anionic multilamellar vesicles, oriented bilayers stacked between glass plates and bicelles. We first investigated the effects of the 14and 21-mer peptides on the conformation of polar headgroups and orientational order of lipid acyl chains by phosphorus-31 and deuterium NMR spectroscopy. The results reveal that the 14and 21-mer model peptides perturb to a greater extent the polar région of phospholipid bilayers, and to a lesser extent the lipid hydrophobic acyl chains. Nitrogen-15 NMR results indicate that the 14and 21-mer peptides réside at the surface of bilayers stacked between glass plates. Also, intermolecular heteronuclear distance measurements confirm the proximity of the 14-mer peptide to DMPC lipid polar headgroups. We hâve also studied the membrane interaction and rotational diffusion of the 21mer peptide in interaction with bicelles by P, H and N NMR. The results reveal that the 21-mer peptide stabilizes the bicelle structure and do not show a circular orientational distribution in the bicelle planar région. Finally, the 21-mer peptide dynamics has been studied by C NMR experiments via the analysis of the number and intensity of spinning sidebands, and the results suggest that the 21-mer peptide is immobilized upon binding. |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | https://corpus.ulaval.ca/jspui/bitstream/20.500.11794/19440/1/24965.pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
