Two French companies are pooling their talents to offer comprehensive services for the isolation and production of target membrane proteins. Company officials say the two organizations work so closely together that they virtually emulate the activities of a single larger firm.
Lyon-based Calixar specializes in upstream processes ranging from identification to crystallization of target membrane proteins. Synthelis, which is located in Grenoble, uses its expertise in multi-expression systems and functional characterization to produce target proteins. The combined services provide clients with intact membrane proteins that maintain their native conformations. This is designed to improve drug discovery, antibody development, vaccine formulation, and structure-based research.
Both companies started in January 2011 and quickly formed an alliance after meeting in Paris at a national awards ceremony that honored innovative startup firms. Their mutual interest and complementary skills in membrane proteins led to the collaboration. “Our customers benefit from this critical mass of know-how and technology,” says Emmanuel Dejean, Ph.D., co-founder and CEO of Calixar.
Membrane proteins make up 20–30% of all cellular proteins, and 70% of them are possible pharmaceutical targets. They could help in the search for therapies for cancer and infectious, neurodegenerative, metabolic, genetic, and other diseases. However, only about 2% of membrane proteins have been structurally characterized, greatly limiting structure-based drug design, according to Dr. Dejean.
Pierre Falson, Ph.D., and Dr. Dejean started Calixar. Dr. Falson invented and patented a technology for extracting membrane proteins at the Centre National de la Recherche Scientifique in Lyon. Calixar holds an exclusive license that covers a series of reagents that extract membrane proteins and crystallizes them without causing denaturation.
“Our principal goal is to avoid denaturation. We use specific patented reagents to carry out the extraction and purification of proteins,” notes Dr. Dejean. A series of 16 reagents has been developed to work in combination with commercial products to optimize the outcome. Some additional “know-how” is also required, he says.
At the core of the technology are macrocyclic molecules called calixarenes, which are detergents with chemical structures that resemble a chalice. The Latin word for chalice is calix, the source of the company’s name.
The reagents work through hydrophobic interactions and a network of salt bridges within the cytosol of membrane proteins. They act as mild surfactants to remove membrane proteins, while preserving the protein’s function and structure for crystallization.
Standard methods for crystallizing membrane proteins rely on detergents to extract them from the cell’s lipid bilayer. These methods, however, damage proteins and cause unfolding and loss of activity, according to Dr. Dejean. “Drugs based on a denatured protein perform inefficiently or have side effects,” he points out.