分子定位系统

In everyday life, the global positioning system (GPS) can be employed to reliably determine the momentary location of one en route to the desired destination. Scientists from the Institute of Physical and Theoretical Chemistry of the University of Bonn have now developed a molecular "GPS" with which the whereabouts of metal ions in enzymes can be reliably determined. Such ions play important roles in all corners of metabolism and synthesis for biological products. The "molecular GPS" is now being featured in the journal Angewandte Chemie. There would be no life on our planet without enzymes. These molecules, control and enable biochemical reactions ranging from digestion to the duplication of genetic information. "Enzymes are spatially complex structures which can have multiple folds, sheets and loops," says Prof. Dr. Olav Schiemann from the Institute for Physical and Theoretical Chemistry of the University of Bonn. In the reaction center of such a "protein knot," which is known as the "active center," is often one or more metal ions. This means that the substance which is to be changed by a chemical reaction attaches to or close to the metal ion. The ion facilitates the breakage or reformation of one or more bonds in the attached substance and the conversion into a new substance arises through the enzyme. Such conversions take place constantly in our stomach, for example, where food is broken down into substances which our body can easily absorb.

Scientists are examining how such essential enzymes work. To do this, they must precisely know how the individual atoms are arranged in these biomolecules. "When we know the whereabouts of the metal ion in an enzyme, we can better understand exactly how the reactions proceed," says Prof. Schiemann. His working group has now determined the position of the active center in an enzyme using a novel method which is reminiscent in principle of the global positioning system (GPS) with which automobile navigation systems work.