分子定位系统

In everyday life, the global positioning system (GPS) can be employed to reliably determine the momentary¹ 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 molecular² "GPS" with which the whereabouts of metal ions in enzymes⁴ can be reliably determined⁵. Such ions play important roles in all corners of metabolism⁶ 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 molecules⁷, control and enable biochemical reactions ranging from digestion⁸ to the duplication of genetic⁹ information. "Enzymes are spatially¹⁰ 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 conversion¹¹ into a new substance arises through the enzyme³. Such conversions¹² 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 precisely¹³ 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 automobile¹⁴ navigation systems work.