By Gary Thomas
Researchers from Ruhr-Universität Bochum (RUB) have developed a novel surface-sensitive spectroscopy method that enables atomic level study of interaction between proteins and pharmaceuticals.
Infrared difference spectroscopy has been used for following the dynamic processes that occur in light-activated proteins. However, molecules related to illness are in proteins that are activated by binding with ligands. A conventional binding technique is not feasible for all proteins. The researchers at RUB evolved a novel method which consisted of combining infrared (IR) spectroscopy with attenuated total reflectance technique for “His-Tagging.” Attenuated total reflectance is a surface-sensitive technique and “His-Tagging” means anchoring of proteins to the measurement surface.
The research team anchored surface proteins on to a germanium crystal. An infrared light was then beamed through this crystal. The light got reflected over and over at the crystal’s boundaries due to attenuated total reflectance, and then spread throughout the crystal. This new technique scores over the Surface Plasmon Resonance technique that is presently being used in the pharmaceutical industry in terms of its atomic resolution capabilities.
The switch protein Ras was the first protein to be tested with the new method. This protein is an important on/off switch for growth of cells. In many cases, oncogenic Ras has been found to be the cause for cancer. The researchers used a His-Tag to fasten Ras to a measurement surface. They then bound the Ras to a ligand to activate it.
Dr. Jörn Güldenhaupt, a researcher at RUB, stated that the technique was highly sensitive and was capable of resolving the signal of a protein layer with a thickness of 5 nm.
The technique was also called as “protein-nanoscope.” This may help tune future pharmaceuticals to treat specific illness-causing proteins.
The study has been reported in the scientific journal “ChemPhysChem.”