Despite we have made great progress in determining crystal structures of membrane proteins, tedious work such as protein engineering and screening for crystallizing conditions is required for successful crystallography studies. In contrast, we can obtain cryo-EM structures for membrane proteins without the need for crystallization. The membrane proteins can be stabilized in detergents or in nanodiscs where membrane proteins are in their membrane-embedded state. Cryo-EM has made rapid progress in resolving the structures of complex membrane proteins. In particular, a large number of high-resolution membrane protein structures have been successfully obtained.

Workflow of cryo-EM structure determination for membrane proteins