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Dynamique de repliement des protéines étudiées par dichroïsme circulaire résolu en temps.

Abstract : To express its biological function, a protein has to adopt a spatial conformation, which is unique and precisely defined. One uses the terms "folding" of the protein towards its "native" structure. Understanding the mechanisms of this process is currently one of the main stakes in biophysical research. In this context, we have set up a new technique to measure circular dichroism. It allows us to follow with precision the structural dynamics of small chiral molecules in liquid phases and over picoseconds to nanoseconds timescales. When applied in the ultraviolet spectral region, it can be used to study the first steps of secondary structures folding. The principle of this technique relies on the measurement of the ellipticity induced by a chiral sample on a linearly polarized incident beam. After having introduced this new method, we will explain how to experimentally make use of it. Then we will compare it to usual techniques employed to measure circular dichroism and will apply it to the study of three molecules (myoglobine, [Ru(phen)3]2+, 1,1'-Binaphthol). Finally, we will examine the first experimental results obtained within the framework of the folding study of model alpha helices. Two techniques that can be used to initiate the folding process will be described: optical excitation of a chromophore located at the extremity of the polypeptide chain, and optical initiation of a temperature jump.
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https://pastel.archives-ouvertes.fr/pastel-00004435
Contributor : Ecole Polytechnique <>
Submitted on : Wednesday, July 21, 2010 - 3:14:01 PM
Last modification on : Friday, October 23, 2020 - 4:37:14 PM
Long-term archiving on: : Friday, October 22, 2010 - 3:47:10 PM

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Claire Niezborala. Dynamique de repliement des protéines étudiées par dichroïsme circulaire résolu en temps.. Biophysique [physics.bio-ph]. Ecole Polytechnique X, 2008. Français. ⟨pastel-00004435⟩

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