Light-Driven Protein Isolation Replaces Affinity Chromatography

Proteins play a vital role in life sciences, underpinning fundamental research, biotechnology, and pharmaceutical development. Researchers at the Technical University of Munich (TUM) have introduced a novel approach that relies on physics rather than traditional chemistry to extract proteins for these applications.

Using short-wave UV light, which is invisible to the human eye, they have developed a more efficient and gentler method for purifying proteins from cell extracts or cultures. This breakthrough offers significant advantages over conventional techniques.

In molecular biology and molecular medicine, pure proteins are essential, whether for research purposes or as active agents. These proteins can be obtained from natural sources or produced in genetically modified cells.

For the past five decades, affinity chromatography has been the go-to method for protein purification. This process involves passing a cell extract or culture medium through a chromatography column packed with a porous carrier material. The target protein binds to this material, allowing it to be separated from other proteins and impurities through solvent washing. Finally, acids or other reagents are used to release the purified protein. However, this final step poses a challenge, as it can compromise the integrity of the isolated protein.

"Instead of chemical reagents, we use a physical mechanism. Our technology is fundamentally different from conventional methods, offering a gentler and more efficient approach," explains Arne Skerra, Professor of Biological Chemistry at TUM.

The “Azo-Tag”: A Molecular Anchor for Protein Purification

The new method still utilizes a chromatography column with a porous carrier material but with a crucial difference: LED lights are integrated around the column, and a small molecular appendage is attached to the target protein.

This appendage, known as the Azo-Tag, was developed by Peter Mayrhofer, Markus Anneser, and Stefan Achatz in collaboration with Arne Skerra at the Chair of Biological Chemistry. It is based on the light-sensitive chemical group “azo-benzene.”

The Azo-Tag functions as a molecular anchor, allowing the target protein to bind to the carrier material regardless of lighting conditions. While bound, contaminants and impurities can be washed away. However, when the column is exposed to mild UV light at a wavelength of 355 nm, the Azo-Tag undergoes a shape change that causes it to detach from the carrier material. This allows the target protein to be eluted in a pure, concentrated, and undamaged form, eliminating the need for additional purification steps.

A More Efficient Alternative with Future Potential

The Chair of Biological Chemistry has already successfully implemented this method to purify antibodies against breast cancer. Currently, a compact version of the system is in use in the lab, with the chromatography column measuring less than a centimeter in diameter. However, researchers believe it can be scaled up for larger applications.

Future advancements are also in the works. As Arne Skerra notes, a patent has been filed for this innovative method. "We are now focusing on automating the process to further enhance efficiency, particularly for high-throughput drug development in the pharmaceutical and biotechnology sectors."

This promising approach could lead to more effective and scalable protein purification, benefiting both research and industry.