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.
A GPS for molecules: Prof. Dr. Olav Schiemann (left) and doctoral student Dinar Abdullin with an image of the enzyme azurine.
(c) Photo: Barbara Frommann/Uni 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.
Like the maze of traffic during rush hour
"The structure of enzymes is frequently, at first glance, just as confusing as the maze of traffic during rush hour," chuckles the physical chemist from the University of Bonn. Similarly to how an individual car is nearly impossible to make out in a large amount of traffic, the metal ion "hides" in the numerous coils and folds of the enzyme. Nonetheless, the position of the vehicle - and also that of the metal ion - can be reliably determined with GPS. Several satellites orbit our planet and indicate through the transit time of signals the distance to a certain point on the earth, for example, a car. The site where the distance spheres of the various satellites intersect is where the car to be located.
The "satellites" consist of the spin labeled amino acid cysteine
The physical chemists from the University of Bonn proceeded similarly. "Our satellites are spin labels," explains doctoral student Dinar Abdullin. These are small organic molecules which have an unpaired electron and which are stable. The researchers distributed six of these "molecular satellites" in their enzyme model "azurine" - a blue protein with a copper ion in the center. Using computer programs, the scientists first tracked the "orbits" of the tiny satellites in the coils of the enzyme. They then determined the distance between the satellites and the metal ion using a spectroscopic method, namely PELDOR, which acts like a ruler on a molecular level. "Similar to the GPS, we were able to precisely determine the position of the active center in the enzyme from this," says Abdullin.
The tool kit of physical chemistry has now gained an elegant additional method. "We developed the method for basic research but it can also be used to clarify the structure of other enzymes," says Prof. Schiemann. A better understanding of substance conversions at active centers is ultimately also the foundation, for example, for industrial drug manufacturing.
Publication: Abdullin D., Florin N., Hagelueken G. and Schiemann O.: EPR based Approach for the Localization of Paramagnetic Metal Ions in Biomolecules, Angewandte Chemie, DOI: 10.1002/anie.201410396
Media contact information:
Prof. Dr. Olav Schiemann
Institute of Physical and Theoretical
Chemistry of the University of Bonn
Johannes Seiler | idw - Informationsdienst Wissenschaft
Mass spectrometry sheds new light on thallium poisoning cold case
14.12.2018 | University of Maryland
Protein involved in nematode stress response identified
14.12.2018 | University of Illinois College of Agricultural, Consumer and Environmental Sciences
The more objects we make "smart," from watches to entire buildings, the greater the need for these devices to store and retrieve massive amounts of data quickly without consuming too much power.
Millions of new memory cells could be part of a computer chip and provide that speed and energy savings, thanks to the discovery of a previously unobserved...
What if, instead of turning up the thermostat, you could warm up with high-tech, flexible patches sewn into your clothes - while significantly reducing your...
A widely used diabetes medication combined with an antihypertensive drug specifically inhibits tumor growth – this was discovered by researchers from the University of Basel’s Biozentrum two years ago. In a follow-up study, recently published in “Cell Reports”, the scientists report that this drug cocktail induces cancer cell death by switching off their energy supply.
The widely used anti-diabetes drug metformin not only reduces blood sugar but also has an anti-cancer effect. However, the metformin dose commonly used in the...
A research team from the University of Zurich has developed a new drone that can retract its propeller arms in flight and make itself small to fit through narrow gaps and holes. This is particularly useful when searching for victims of natural disasters.
Inspecting a damaged building after an earthquake or during a fire is exactly the kind of job that human rescuers would like drones to do for them. A flying...
Over the last decade, there has been much excitement about the discovery, recognised by the Nobel Prize in Physics only two years ago, that there are two types...
12.12.2018 | Event News
10.12.2018 | Event News
06.12.2018 | Event News
14.12.2018 | Power and Electrical Engineering
14.12.2018 | Physics and Astronomy
14.12.2018 | Physics and Astronomy