Agenda de l'ENS de Lyon

Probing biomolecular dynamics and interactions by combining chemical synthesis and NMR spectroscopy

lun 26 sep 2022


CRMN de Lyon

5 rue de la Doua, 69100 VILLEURBANNE


Soutenance de thèse de Mme Emeline MESTDACH sous la Direction de M. Loïc SALMON

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My thesis focused on the development of novel biomolecular NMR methodologies to characterize dynamics and interactions of biological macromolecules, by exploring novel horizons of biology, chemistry and NMR spectroscopy. My work first focused on a transfer RNA (tRNA), an essential component of the translation. Modulation of tRNA dynamic was probed using NMR 15N spin relaxation, in the context of tRNA maturation. Here, multiple-field relaxation rates, were measured and analyzed to capture the fast dynamics of this system. The second project was centered on micro-RNAs (miRNAs), key genetic regulators, capable to block messenger RNA (mRNA) translation. The let-7 miRNA and its targets were chemically synthesized to incorporate 19F probes, allowing to describe the interaction between let-7 and its target mRNAs by NMR. The third study aimed at characterizing a protein involved in the T5 bacteriophage infection of bacteria, and probe its interaction with its bacteria receptor protein. Resonance assignment of LLP the T5 protein involved in phage infection has been performed, as well as the 3D structure characterization. Spin relaxation was used to probe LLP dynamics and titration experiments with the bacteria receptor allowed to reveal the binding interface. Finally, the last project involves the dynamic study of an aquaporin, a membrane protein acting as water channel, by solid-state NMR. Cross-polarization with variable contact time experiments were measured and analyzed as well as multiple fields spin relaxation to investigate its dynamics. All these examples exemplify how NMR spectroscopy can probe complex dynamic processes in various contexts.


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