The CL-7 Affinity Tag System Solution

The Importance of Proteins

All processes taking place in a living organism are caused by the actions of proteins. Enzymes, hormones, antibodies, hemoglobin, and collagen are all made of proteins. And proteins do all of the work—cellular maintenance, defense, transport, reproduction. Understanding the structure, and function of proteins is critical in life science research and medicine, and is the driving force since nearly all drugs act on proteins to enhance or inhibit natural processes.

The process of purifying proteins can often become a major bottleneck in research, as it did for Dr. Dmitry Vassylyev, a crystallographer. Since he couldn’t obtain the protein purity and yield he needed with existing commercially-available methods, he set out to find a better, faster, cost-effective solution.

Dr. Vassylyev knew he didn’t want to just create a marginally better method, so he scoured the entire PubChem database of all known molecular compounds to find the best one for his work. He looked for a binding system with extraordinary binding strength; one that could withstand harsh conditions—such as high temperature and high-salt concentration—so impurities would be washed out leaving the desired target protein intact.

The Challenge of Protein Research

Protein purification is the basis for many biochemical and biomedical studies. Purity and yield are particularly crucial for high-resolution structural analysis and industrial protein production, where it has to meet the high-yield, high-purity, and high-activity (HHH) requirement. However, the HHH purification of many proteins or protein complexes—especially challenging biological molecules such as eukaryotic, membrane, toxic, and DNA/RNA-binding proteins—remains a difficult, target-dependent, and time-consuming, multi-step process.

For many scientists, protein production is solely a means to an end—not their primary objective—and they find the production process to be time-consuming and inefficient. Worse, in a multi-step process, each purification step results in more target protein being lost in the process.

A Single-Step Purification Solution

Our novel CL-7 affinity tag system enables purification in a single step, takes only a few hours, and produces yields of 300mg of high-purity protein per liter.

This technology platform was born from Dr. Vassylyev’s need to resolve his own headaches from protein purification. He perfected the CL-7 system by testing it with five of the most notoriously challenging proteins, compared it to the best known commercial affinity chromatography offerings, and then shared his results in one of the most significant peer-reviewed scientific journals, the Proceedings of the National Academy of Sciences.

Our CL-7 system is a breakthrough for scientists who need larger amounts of high-purity proteins, and need to isolate them in a shorter amount of time. Our CL-7 system successfully merges the best qualities of commercially-available affinity methods, with highly-specific binding due to use of a biological binding molecule. It also has ultra-high affinity, high tolerance to salt and other additives, and exceptional yield and purity.

In simple terms, this is a uniquely robust and efficient method. The system is simple, reusable, and also applicable to pulldown and kinetic activity/binding assays. This new tag has binding affinity 4-7 orders of magnitude higher than other methods, which results in ultra-efficient purification of even the most complex proteins.

The Benefits of Using the CL-7 System

The benefits and potential benefits of this CL-7 system:

  • Less time to create high purity proteins with a 100x yield improvement.
  • An efficient and potentially universal tool for high-throughput studies of many significant biological systems.
  • Ability to facilitate large-scale production of biologically active proteins and form the basis for high-throughput protocols to characterize intermolecular interactions; 


TriAltus Bioscience holds the exclusive, worldwide license to the CL-7 protein purification technology platform. It was licensed from the University of Alabama at Birmingham (UAB) in Birmingham, Alabama USA.  An international patent filing has been made with protection being sought in the United States, Europe, and other major markets. The CL-7 purification technology is available for research use. For commercial use or resale, contact us at to discuss commercial licensing.