Monolayer two-dimensional crystallization of membrane proteins, Methods Mol Biol 2013, 955:59-71

This method of two-dimensional crystallization of proteins on a lipid monolayer aims at producing 2D crystals of membrane proteins, which can provide structural information at high resolution by electron crystallography. A lipid monolayer is spread over the whole air–water interface of a drop, which provides a substrate for protein binding. The protein of interest is then adsorbed onto the lipid monolayer and forms a closely packed layer. The reconstitution step of the membrane protein into a lipid bilayer is realized by elimination of detergent. The combined effect of the elevated protein concentration, the alignment of the protein on the lipid monolayer, and the fluid monolayer film properties are conducive, in some cases, to the formation of 2D crystals. The use of locally fluorinated lipids in avoiding solubilization of the lipid monolayer by detergents is presented and discussed.