Relating structure, biomechanics and function of single membrane proteins

One of the greatest challenges of biophysics is to understand how membrane protein sequences relate to the local forces that dynamically control their structure and drive their function. AFM is one of the most powerful techniques to address this problem, however, most of the single membrane protein unfolding AFM studies available fail to relate the potential barriers observed to specific molecular interactions relevant for the protein function. In some of our recent papers, we have combined membrane indentation with AFM1, AC-force spectroscopy2, AFM unfolding and extraction of model peptides inserted planar lipid bilayers at different speeds3, unfolding and extraction of bacteriorhodopsin (bR) from purple membranes4 and comparison of pulling experiments with molecular dynamics simulations3 to relate structure, nano-biomechanics, local hydration, mechanical properties and function of membrane proteins. In particular, retinal proteins convert the energy of a single photon into large structural changes subsequently used to carry out various tasks. This is achieved by a complex combination of local dynamical interactions controlling the protein biomechanics, allowing efficient amplification of the retinal isomerization. In the case of the retinal containing proton