Water is no passive spectator of biological processes; it is an active participant. Protein folding is thus a self-organized process in which the actions of the solvent play a key role.
So far, the emphasis in studies of protein folding processes has been on observation of the protein backbone and its side chains. Researchers led by Martin Gruebele and Martina Havenith have now been able to detect changes in the protein–water network during protein folding in real time.
As they report in the journal Angewandte Chemie, this team of scientists at the University of Illinois (Urbana, USA) and the Ruhr University in Bochum (Germany) used a spectroscopic technique called KITA (kinetic terahertz absorption) to make their observations.
Terahertz (THz) radiation consists of electromagnetic waves in the submillimeter range, putting it between the infrared and microwave ranges. Efficient sources of THz radiation are now available, making it possible to directly measure the absorption of biomolecules in aqueous buffers on the picosecond time scale. Both the skeletal movements of proteins and the collective motions of water molecules surrounding proteins occur on this time scale. The research team recently demonstrated that THz-range absorption spectroscopy is a sensitive method for the investigation of the water shell that surrounds proteins. In the layers immediately surrounding the protein, the water molecules are networked to each other differently than in pure water. Their absorption of THz radiation at certain frequencies is thus changed.
The way in which a protein folds to a very large extent determines its function. The folding process is very fast. The movements of the protein backbone influence the solvent, and the dynamics of the solvent can in turn influence the dynamics of the protein—thus playing an important role in the folding process. Kinetic THz absorption (KITA) registers the damping and phase-shifting of an electrical THz field caused by the folding of a protein. Comparison with results obtained by other methods confirms that KITA detects reorientations of the interactions between a protein and its water shell in an early phase of the folding process.
Author: Martin Gruebele, University of Illinois, Urbana (USA), http://www.scs.uiuc.edu/%7Emgweb/
Title: Real-Time Detection of Protein–Water Dynamics upon Protein Folding by Terahertz Absorption Spectroscopy
Angewandte Chemie International Edition 2008, 47, No. 34, 6486–6489, doi: 10.1002/anie.200802281
Blood test shows promise for early detection of severe lung-transplant rejection
23.01.2019 | NIH/National Heart, Lung and Blood Institute
Evolution of signaling molecules opens door to new sepsis therapy approaches
23.01.2019 | Technische Universität München
So-called bifacial stem cells are responsible for one of the most critical growth processes on Earth – the formation of wood.
Immune cells called macrophages are supposed to serve and protect, but cancer has found ways to put them to sleep. Now researchers at the Abramson Cancer...
The scientific and political community alike stress the importance of German Antarctic research
Joint Press Release from the BMBF and AWI
The Antarctic is a frigid continent south of the Antarctic Circle, where researchers are the only inhabitants. Despite the hostile conditions, here the Alfred...
World first experiments on sensor that may revolutionise everything from medical devices to unmanned vehicles
The new sensor - capable of detecting vibrations of living cells - may revolutionise everything from medical devices to unmanned vehicles.
Dead and alive at the same time? Researchers at the Max Planck Institute of Quantum Optics have implemented Erwin Schrödinger’s paradoxical gedanken experiment employing an entangled atom-light state.
In 1935 Erwin Schrödinger formulated a thought experiment designed to capture the paradoxical nature of quantum physics. The crucial element of this gedanken...
16.01.2019 | Event News
14.01.2019 | Event News
12.12.2018 | Event News
23.01.2019 | Physics and Astronomy
23.01.2019 | Materials Sciences
23.01.2019 | Life Sciences