Magnetic Labels: Protein Measurements in the Cell

Photo: Horseshoe magnet attracts balls

Researchers from Konstanz develop method to exactly determine the structure of proteins in their natural environment; © Le Moal

A network of chemists at the University of Konstanz has developed a method to study protein structures by means of magnetic labels. The ingenious thing about it is that the magnetic labels are directly incorporated inside the cell when the protein is naturally biosynthesized.

"Unnatural amino acids with special chemical or biophysical functions that are directly incorporated into proteins in the cell have been known for years. However, despite all efforts it has been impossible so far to develop a magnetic unnatural amino acid. Now we have achieved a real breakthrough", says the chemist Dr. Daniel Summerer about the research project, which has been conducted in collaboration with the working group of the physical chemist Dr. Malte Drescher. "This has brought us a significant step closer to the final objective of measuring the structure and dynamics of proteins directly in the cell with high precision", Summerer explains.

Proteins that have been modified with the unnatural amino acids from Konstanz can be measured by means of electron paramagnetic resonance spectroscopy (EPR-spectroscopy). Interacting magnetic labels are introduced into strategically selected protein sites. "Measuring the strength of the magnetic interaction enables us to deduce the distance", explains Drescher. "The structure of the protein can be determined by measuring several distances on the nanometer-scale", Drescher reveals the key principle.

In further steps the scientists intend to implement their method, for which they have filed a patent, for the study of protein structures in cells: "Our vision is that we will use our method to investigate biologically relevant systems that play a role in e.g. the Parkinson's disease or in regulating the expression of disease-relevant genes", Drescher provides an outlook for the continuation of the research works.; Source: University Konstanz