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Proteins are essential components of life sciences, playing crucial roles in diverse areas—ranging from fundamental research and biotechnological applications to the design and production of pharmaceuticals. A team at the Technical University of Munich (TUM) has pioneered a method that leverages physics rather than traditional chemistry to extract the necessary proteins. Through the use of short-wave UV light that is not visible to the human eye, they have accomplished a new technique for purifying proteins sourced from cell extracts or cultures. This innovative method not only enhances efficiency but also minimizes potential damage compared to conventional techniques.
In the fields of molecular biology and molecular medicine, the requirement for highly purified proteins is prevalent, as these are crucial for a variety of studies or therapeutic uses. Proteins are typically isolated from natural environments or created using genetically modified organisms.
For many years, affinity chromatography has stood out as the preferred method for protein purification. This approach involves passing cell extracts or culture media through a chromatography column filled with a porous matrix. Here, the target protein adheres to the carrier material, enabling separation from other proteins and impurities through solvent washing. The final step often requires detaching the purified protein using acids or other agents, which poses a risk of damaging the protein.
To address these limitations, Arne Skerra, Professor of Biological Chemistry at TUM, has introduced a novel method that pivots away from chemical agents. “We utilize a physical mechanism instead of chemical reagents. Our technology fundamentally differs from traditional methods by being both gentler and more efficient,” explains Skerra.
The “Azo-tag”: a molecular appendage that anchors
This innovative method also employs a chromatography column with a porous carrier, but introduces key differences: LED lights encircle the column, and a small molecular appendage is affixed to the target protein.
Named the Azo-Tag, this minimalistic extension was developed by Peter Mayrhofer, Markus Anneser, and Stefan Achatz, collaborating with Skerra based on light-sensitive “azo-benzene” compounds. The Azo-Tag is capable of altering its form when exposed to light, acting as a molecular anchor for the target protein. In both daylight and darkness, the protein binds selectively to the column’s carrier material via this anchor, allowing extraneous substances and contaminants to be washed away without losing the target protein.
However, when the LED lights are activated and the column is exposed to gentle UV light at a wavelength of 355 nanometers, the tag changes shape. Essentially, this causes it to detach from the carrier material, enabling the target protein, along with its Azo-Tag, to be eluted from the column in a pure, concentrated form, undamaged and ready for immediate use in subsequent research without needing further purification.
Improved efficiency over conventional chromatography and prospects for advancement
The Chair of Biological Chemistry is already implementing this method routinely and has successfully purified antibodies for breast cancer research. Currently, the team operates a compact version of the apparatus, with a chromatography column measuring less than one centimeter in diameter, but there are plans for larger-scale production.
Looking ahead, Skerra mentions ongoing efforts, alongside his colleagues, to file a patent for this innovative technique: “We are actively working on automating these processes to enhance their efficiency, particularly in high-throughput drug development for pharmaceutical and biotechnology firms.”
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