Improving Membrane Memtics for Structural Determination of Membrane Proteins

Chen Zhao^1,2, Xiao Tao^1,3 and Roderick MacKinnon¹

1. The Rockefeller University, HHMI
2. University of Florida
3. Genentech, Inc.

Transmembrane proteins comprise ~30% of the human proteome and play vital roles in establishing membrane potential, transporting solutes, and signal transduction. Structure determination of these membrane proteins relies on stabilizing their transmembrane domains via membrane mimetics. Despite the remarkable success of the traditional membrane mimetics such as detergents or lipid nanodiscs, they possess several limitations. Firstly, several studies found that detergents or lipid nanodiscs prefer specific conformations of the membrane protein of interest, leading to limited correlation between atomic structures and physiology. In addition, the usage of dispersive agents could strip away weakly bound lipid and protein molecules, precluding molecular interactions that would normally occur in cells. In response to these challenges, we introduce a method to determine high-resolution transmembrane protein structures directly from native cell membrane vesicles using single particle cryo-electron microscopy (cryo-EM), without the need to remove them from the membrane environment using dispersive reagents. This talk contains two parts. In the first section, I will review the limitations of the current structural biology approaches and give a specific example focusing on ion channel TRPM3. In the second half, I will present our recent work on determining the structures of ion channel Slo1 from cell membrane-derived vesicles. We believe our new method presents an exciting future direction for the structural characterization of transmembrane proteins.

This is an invited talk by Dr, Matthew Eddy from University of Florida. I accidentally submitted this abstract to the wrong session before. I apologize for the delay.