Molecular mechanism of membrane-associated folding and unfolding
We study thermodynamics and kinetics of polypeptide interaction with lipid bilayer of membrane to elucidate the molecular mechanism of membrane-associated folding and unfolding. Our model system is pHLIP peptides, which undergo conformational changes triggered by changes of pH. Partition of the peptides into bilayer triggers formation of helical structure (coil-helix transition), while exit promotes unfolding (helix-coil transition). We monitor changes in fluorescence and circular dichroism during pHLIPs insertion into membrane and folding, as well as exit and unfolding in steady-state and kinetics modes. Our aim is to elucidate molecular mechanism of membrane-associated folding and unfolding and introduce physical model based on the experimental results and guided by the approaches of statistical physics, kinetic theory and molecular dynamic calculations in collaboration with our partners.