2026-09-26T04:39:17Zhttps://orbi.uliege.be/oai/request

oai:orbi.ulg.ac.be:2268/1595282026-09-01T13:28:03Zcom_f00col_f02class_f05

master thesis http://purl.org/coar/resource_type/c_bdcc info:eu-repo/semantics/masterThesis open access http://purl.org/coar/access_right/c_abf2 info:eu-repo/semantics/openAccess https://orbi.uliege.be/page/user-license Contribution à l’étude des peptides obliques impliqués dans des transconformations Contribution to the Study of Tilted Peptides Involved in Protein Transconforamtion Crowet, Jean-Marc Brasseur, Robert Lins, Laurence Paquot, Michel 2003-09-11 86 https://orbi.uliege.be/handle/2268/159528 info:hdl:2268/159528 https://orbi.uliege.be/bitstream/2268/159528/1/TFE_JMC.pdf fr Life sciences Biochemistry, biophysics & molecular biology Sciences du vivant Biochimie, biophysique & biologie moléculaire The study of the amyloidogenic proteins is important to understand the transconformational processes. These proteins have a unique common feature : they undergo a conformational change leading to the formation of highly structured fibrils that are mainly β conformed. These proteins are difficult to study experimentally due to their low solubility and their tendency to aggregate rapidly. Recently, tilted peptides have been detected in such proteins. These peptides are short fragments (11 to 18 residues) that adopt a tilted orientation when they interact with a hydrophilic/hydrophobic interface. This property is due to the presence of an asymmetric hydrophobicity gradient when they are helical. Those peptides are able to destabilize organized molecular systems. Amyloidogenic proteins containing such peptides are the PrP protein, the Aȕ peptide, and the bacterial prions Ure2p and Sup35p. The presence of such fragments in transconformational proteins has led to the hypothesis that tilted peptides could be implied in the conformational change of amyloidogenic proteins. These peptides could play a role through their destabilizing properties and/or their structural lability. The aim of this work was to detect tilted peptides among other amyloidogenic proteins by molecular modelling. One of the detected peptides is tested experimentally to evidence its lipid destabilizing properties. Five tilted peptides from four different proteins have been detected among 27 amyloidogenic proteins. The tilted fragment from the α-synuclein sequence, a protein involved in Parkinson disease, has been synthetized and tested for lipid fusion. The fusogenic assays pointed out its destabilizing properties. These results support the hypothesis that tilted peptides could be involved in transconformational processes. ULiège. GxABT - Liège Université. Gembloux Agro-Bio Tech Etude de l’implication des peptides obliques dans les phénomènes de transconformation Centre de Biophysique Moléculaire Numérique