Probing Ultrafast Stereochemical Dynamics by Femtosecond Electronic Circular Dichroism Spectroscopy

Description du projet

Lumières, caméra, action: observer des interactions moléculaires dynamiques en mouvement

La chiralité est une propriété intéressante de nombreuses molécules biologiques dans lesquelles les images symétriques – les mêmes atomes attachés aux mêmes endroits – ne peuvent être superposées. Les mains humaines en sont un parfait exemple – des images symétriques dans lesquelles l’auriculaire se superpose au pouce lorsque vous posez une main sur l’autre. La lumière polarisée peut sonder les molécules chirales avec une grande sensibilité structurelle, et elle est couramment utilisée pour étudier des molécules biologiquement importantes telles que les protéines, les acides nucléiques, les glucides et les médicaments. Le projet CHIRALSCOPY, financé par l’UE, associe cette technique de sondage structurel très sensible à la spectroscopie optique ultrarapide pour permettre la réalisation de «films» des changements structurels qui se produisent au cours des réactions chimiques et des processus biologiques.

Objectif

Since the structure of a (bio)-molecule is crucially linked to its biochemical functions, following its evolution in the course of a chemical reaction or biological process would allow one to gain fundamental insights into the reaction mechanisms and pathways. This calls for optical spectroscopy techniques capable of recording structural dynamics with high time resolution, down to the femtosecond regime. Circular dichroism (CD), i.e. the difference in absorption of left- and right-handed circularly polarised light, is a sensitive probe of the structure of chiral molecules. CHIRALSCOPY aims to develop an innovative time-resolved CD spectrometer which combines the structural sensitivity of steady-state CD spectroscopy with the high time resolution of ultrafast nonlinear optical spectroscopy. CHIRALSCOPY will adopt an innovative approach which directly measures in the time domain the chiral light field from a molecule by combining interferometric detection with optical heterodyne amplification. The state-of-the-art time-resolved CD instrument will be used to elucidate structural dynamics during a prototypical biochemical reaction. CHIRALSCOPY will equip the Experienced Researcher with new knowledge and skills in advanced optical technologies and biophysics, thus broadening his scientific background and enhancing his prospects as an independent researcher. At the same time, the Action and the Host Institution will benefit from the advanced knowledge in ultrafast spectroscopy acquired by Researcher during his PhD thesis. CHIRALSCOPY promises to open new vistas in the field of ultrafast optical spectroscopy enabling one to interrogate molecular dynamics with femtosecond temporal resolution and exquisite structural sensitivity−thus realising the chemist’s dream of a capturing a ‘molecular-motion-picture’ of a chemical reaction.