Screening Membrane Protein Crystallization Conditions
in Lipidic Cubic Phase using LCP-FRAP by Dr. Vadim Cherezov
About Vadim Cherezov, PhD
Dr. Cherezov is a professor in the Chemistry Department at the University of Southern California (USC). The Cherezov Lab at USC focuses on discovering the structure and function of membrane proteins and extensively uses Lipidic Cubic Phase (LCP) as a tool in their research. To learn more about Dr. Cherezov and the Cherezov Lab at USC, please click here.
One of the main factors for successful LCP crystallization is the ability of the protein to diffuse within the lipid bilayer. The diffusion rate of the protein is influenced by protein aggregation, structural properties of the LCP, and the chemical environment. The diffusion rate can be determined by Fluorescent Recovery After Photobleaching (FRAP), which measures the amount of time required for the fluorescence intensity of a tagged protein to reestablish itself within a small area in the LCP drop that has been subject to optical bleaching. Using FRAP you can screen your crystallization experiment in under 50 minutes to determine the mobile fraction of your protein and whether or not that condition is conducive to forming protein crystals. FRAP has been found to be most useful for studying G protein coupled receptor (GPCR) proteins.