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Recherche par modélisaion moléculaire de signatures RMN et DC caractéristiques pour les coudes β et y dans les peptides bioactifs.

Abstract : The aim of this work is to identify NMR and CD characteristic patterns for β- and γ-turns in bioactive peptides by molecular modelling. With helices, β- and γ-turns constitute favoured recognition motifs in bioactive peptides by their targets. Even though several classes of turns with different geometries exist in polypeptide structures (2 γ-turn types and 12 β-turn types), few experimental tools are available for their characterization. Thus, only 4 types of β-turns (I, I’, II et II’) have been, at present, described by NMR and there are no reliable reference CD spectra for turns. In order to extend the NMR data for all β- and γ-turn types, we analyzed NMR structural parameters (inter-hydrogen distances and ᶾJʜɴ-ʜꭤ coupling constants) in a representative peptide model dataset extracted from the PDB. The inter-hydrogen distance analysis allowed to identify specific NMR patterns for the two γ-turn types and for four β-turn types (IV₁, IV₂,, VIb and VIII). ᶾJʜɴ-ʜꭤ coupling constant may be used to confirm the identification and to remove ambiguities. Then, we simulated the reference CD spectra of model peptides adopting type I, I’, II and II’ β-turn conformations by combining molecular dynamic simulations and TDDFT computations. These computations allowed to determine two families of specific CD spectra : types I/II’, on one side and types I’/II, on the other. All these results indicate that the turns do not present the same patterns in both techniques. The combination of NMR and CD could therefore allow a better identification of the nature and the different types of turns.
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https://tel.archives-ouvertes.fr/tel-03112593
Contributor : Abes Star :  Contact
Submitted on : Sunday, January 17, 2021 - 1:01:38 AM
Last modification on : Sunday, January 17, 2021 - 3:24:59 AM

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  • HAL Id : tel-03112593, version 1

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Mattia Migliore. Recherche par modélisaion moléculaire de signatures RMN et DC caractéristiques pour les coudes β et y dans les peptides bioactifs.. Chimie analytique. Normandie Université, 2020. Français. ⟨NNT : 2020NORMR001⟩. ⟨tel-03112593⟩

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