Abstract: In this seminar, I will present a summary of interdisciplinary and collaborative studies recently performed on pentameric ligand-gated ion channels (a class of synaptic channel-receptors) from the structural point of view. I will insist on the fact that getting high-resolution structures is highly needed though it does not constitute our final goal, and I will describe some modeling and experimental approaches that can be used to probe the system's dynamics - the understanding of which is crucial for relating the structure(s) of the system to its biological function. In particular, I will highlight the importance of being able to provide a correct treatment of the solvent organization around the system, and will illustrate this by describing Poisson-Boltzmann related methods (corresponding to a mean-field level of approximation) and their applications to describe data output from X-ray scattering experiments in solution. I will also give hints at ways to improve these predictions by going beyond the mean-field level of approximation.

 

About the Speaker: Dr. Frédéric Poitevin is currently a postdoctoral fellow at the Institute for Theoretical Physics (IPhT), CEA Saclay, France. He obtained his Bachelor and Master Degree in Chemistry from Ecole Normale Supérieure and his PhD in 2012 from the University of Paris-Diderot Paris 7. During his PhD work in Dr Marc Delarue’s lab at Institut Pasteur, he carried out experimental and computational work to illustrate the structural details of conformational change and transport through the pentameric ligand-gated ion channels. He was also involved in the development of AquaSAXS software package for SAXS experimental data processing and analysis. More recently, he is working on the computation of solvent (ion and water) condensation on proteins and its effect on the interpretation of SAXS data, in collaboration with Prof. Henri Orland at CEA Saclay and Prof. Sebastian Doniach at Stanford. He has published 10 papers so far in high impact journals, including one in Nature, one in Nature Struc. Mol. Biol. and 2 in PNAS.