Skip to Main content Skip to Navigation
New interface
Theses

Etude d'un système biomimétique simple : diffusion brownienne et mobilité électrophorétique d'une protéine membranaire modèle insérée dans une bicouche lipidique supportée

Abstract : After the genome, the new challenge is the proteome. We have progressed toward electrophoretic separation of membrane proteins in a medium that they love, a supported lipid bilayer. The main parameter, measured by FRAPP, was the diffusion coefficient of different objects (lipids, proteins). Studying bilayer behaviour has showed that, on particular supports and in a given temperature range, ripple phase can exist, despite the proximity of the support. Adding salt decreases coulombic interactions which turns to increase the diffusion coefficient over several orders of magnitude, reaching the value for a free-standing bilayer in the fluid phase, meanwhile the main characteristic steps of the global gel/fluid transition are still observed. Estimation of the value of the interaction energy has been made and compared to results of a preliminary DSC study. α-Hémolysin self-inserts spontaneously as an heptameric pore in supported bilayers and diffuses freely. Incubating in a gel/fluid mixture leads to protein complex formation. Diffusion varies with size as 1/R2, R being the equivalent radius of the inserted part of the object. Applying an electric field results in an electrophoretic motion where direction and magnitude are modulated by the charge of the object. Electrophoretic mobility varies also as 1/R2. Size dependence, magnitude of mobilities and a simple building protocol allow to hope carrying out soon a real electrophoretic separation of a protein mixture.
Complete list of metadata

https://theses.hal.science/tel-00790343
Contributor : Frédéric Harb Connect in order to contact the contributor
Submitted on : Wednesday, February 20, 2013 - 11:57:12 AM
Last modification on : Tuesday, October 19, 2021 - 10:52:10 PM
Long-term archiving on: : Tuesday, May 21, 2013 - 9:23:03 AM

Identifiers

  • HAL Id : tel-00790343, version 1

Collections

Citation

Frédéric Harb. Etude d'un système biomimétique simple : diffusion brownienne et mobilité électrophorétique d'une protéine membranaire modèle insérée dans une bicouche lipidique supportée. Biophysique [physics.bio-ph]. Aix-Marseille Université, 2012. Français. ⟨NNT : ⟩. ⟨tel-00790343⟩

Share

Metrics

Record views

261

Files downloads

592