The research team has combined technologies to develop a new biotech technique that promises to accelerate research into protein therapies. A Northwestern-led synthetic biology research team has combined technologies to develop a new biotech technique that promises to accelerate research into protein therapies that could one day become the next defense against antibiotic-resistant super germs or the next new drug. The study was published in the journal Nature Chemical Biology.

Glycosylation, which is the attachment of sugars to proteins, plays a critical role in how proteins form and work in cells and how cells interact with other cells. It is also important in the study of disease and biotechnologies. Together they developed a new platform for characterizing and optimizing sequences for making glycoproteins using cell-free protein synthesis and mass spectrometry.

The new technique promises to vastly speed up the time needed to test compounds for potential new drugs. As recent as a few decades ago, drugs were based on natural products that were tediously isolated and characterized from plants and other natural sources. But once chemists learned to make libraries of large numbers of molecules which today number in the millions and once engineering brought laboratory automation forward as a tool, they were able to rapidly test millions of compounds within a few weeks to identify good starting points for drug development.

The author explained in synthetic biology, the cycle time to test each enzyme-substrate interaction can take weeks or months. These tags are important because glycosylation is present in 70% of protein therapeutics already approved or in preclinical evaluation.

The process works by combining three techniques from Northwestern laboratories:

1. Cell-free protein synthesis, Jewett's method of producing proteins without using living, intact organisms

2. Protein glycosylation, a specialty of Jewett's lab that allows researchers to rapidly create and test a large number of enzymes in test tubes

3. SAMDI (self-assembled monolayers for matrix-assisted desorption/ionization) mass spectrometry from Mrksich's lab, a super-fast, low-cost, and "label-free" method of measuring biochemical activities on a surface

They developed peptide arrays where we have one plate about the size of your hand that has approximately 1,500 circular regions on it. Each of those regions has attached to it a different peptide tag, and we can apply the enzyme solution evenly across the full array and each of the peptide tags can then be glycosylated.

After the plate is rinsed, the entire array can be analyzed by mass spectrometry, which quantifies the amount of glycosylation of each peptide. They can evaluate thousands of distinct peptide tags to identify the optimal ones for glycosylation that we then move forward. The result is not only much faster but also delivers much more detailed data.

This technique allows us to ask much more precise and scientific questions in this area that would have been previously possible. The new knowledge that is derived could really be game-changing in terms of our ability to engineer glycoproteins with desirable traits.