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Dynamique conformationnelle des protéines étudiée par dichroïsme circulaire résolu en temps

Abstract : Proteins are the most important macromolecules in the living world. They are in a way the working bees of all the living organisms. They perform many functions such as enzymatic, nervous, motion functions ; they can transport smaller molecules that allow the cells to feed and function. During this three years of Thesis, we got interested in different aspects of the conformational changes that can happen in proteins. All these phenomena have been studied by a common method : the measurement of time resolved circular dichroïsm. What is interesting is that circular dichroïsm can give quantitative informations on a chromophore position or on the folding of an alpha-helix which is a big advantage over many other methods. First, we studied the influence of the solvant on the poly(glutamic acid) folding and observed differences in the dynamics and thermodynamics of the phenomenon depending wether the peptide was dissolved in water or in heavy water. We then studied, by a different method, a key step of the PYP's chromophore relaxation. Finally we tried to approach the movement of alpha-helices in bacteriorhodopsin and opened the question about conformational changes that have not been predicted or observed yet. Thanks to different measurement methods, we have been able to study phenomena on timescales from picoseconds to microseconds. We hope that these methods will be extended to the study of many other folding mechanisms.
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https://pastel.archives-ouvertes.fr/pastel-00843425
Contributor : Lucille Mendonca <>
Submitted on : Thursday, July 11, 2013 - 12:31:24 PM
Last modification on : Wednesday, January 23, 2019 - 10:29:00 AM
Long-term archiving on: : Wednesday, April 5, 2017 - 9:49:31 AM

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Lucille Mendonca. Dynamique conformationnelle des protéines étudiée par dichroïsme circulaire résolu en temps. Biophysique [physics.bio-ph]. Ecole Polytechnique X, 2013. Français. ⟨pastel-00843425⟩

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