Membrane proteins expression in vivo and in vitro

Laurent Catoire, Oana Ilioaia, Sandrine Masscheleyn, Bruno Miroux, Elodie Point, Dror Warschawski, Francesca Zito

Among the difficulties conventionally encountered in the study of membrane proteins, we find the problems of aggregation, heterogeneity of the purified sample, presence of detergent that disrupts the crystallogenesis, and finally the very low level of expression of membrane proteins in heterologous systems.

In bacteria, and given the total absence of compartmentalization, all the steps of transcription, translation, addressing and folding of proteins in the membrane of the bacteria have to be held in a synchronized way.

Our laboratory develops two complementary approaches to produce our membrane proteins of interest :

• the in vitro synthesis of proteins from bacterial extracts
• the in vivo expression of bacteria mutants suiting the overproduction of membrane proteins