Simple screening method for improving membrane protein thermostability

Biochemical and biophysical analysis on integral membrane proteins often requires monodisperse and stable protein samples. Here we describe a method to characterize protein thermostability by measuring its melting temperature in detergent using analytical size-exclusion chromatography. This quantitative method can be used to screen for compounds and conditions that stabilize the protein. With this technique we were able to assess and improve the thermostability of several membrane proteins. These conditions were in turn used to assist purification, to identify protein ligand and to improve crystal quality.

► Monodispersity and thermostability are known parameters for protein crystallizability.
► We determine Tm of membrane proteins from size exclusion chromatography profiles.
► This method can be used to search for crystallization conditions, additives and putative substrates.