Biophysicists in Bochum have discovered a diode for protons: just like the electronic component determines the direction of flow of electric current, the “proton diode” ensures that protons can only pass through a cell membrane in one direction. Water molecules play an important role here as active components of the diode.
The researchers led by Prof. Dr. Klaus Gerwert (Chair of Biophysics at the RUB) were able to observe this through a combination of molecular biology, X-ray crystallography, time-resolved FTIR spectroscopy and biomolecular simulations. They report in the current international online edition of the journal Angewandte Chemie.
Protons drive the protein turbines
The proton diode plays an important role in the energy production of cells. Light-driven proton pumps - certain proteins that traverse the cell membrane - eject protons out of the cell, so that excess pressure is generated outside “much like the water pressure at a dam”, explains Prof. Gerwert. Elsewhere, the protons push back into the cells to compensate the concentration gradient, and thereby drive the turbines of the cell, proteins known as ATPases. The energy thus released is converted into the universal fuel of the cells, ATP (adenosine triphosphate). “This process is a kind of archaic photosynthesis” explains Prof. Gerwert. “The light energy is ultimately converted into usable energy for the organism”.
We used to believe in chance
The details of these processes are the subject of research. In particular, the role of water molecules in proteins has long been unclear. “Previously it was believed that the water molecules blundered into the proteins by chance, and fulfilled no particular function”, says Gerwert. Manfred Eigen, born in Bochum in 1967, was awarded the Nobel Prize for chemistry because he was able to explain why water and ice protons are such rapid conductors. The current work shows that proteins also use precisely this mechanism and that the water molecules do indeed carry out an active function in the protein.
Water is as important as amino acids
This result supports the hypothesis drawn up by Klaus Gerwert in 2006 in Nature that protein-bound water molecules are just as important catalytic elements for the function of proteins as amino acids, the building blocks of life. Consequently, the Bochum biophysicists have devoted their work in Angewandte Chemie to Manfred Eigen. Eigen also published his central thesis on proton transfer in water in Angewandte Chemie in 1964. Klaus Gerwert was inspired by Manfred Eigen’s winter seminars in Klosters.
Film instead of fixed image
The Bochum researchers were able to achieve their results in an interdisciplinary approach through a combination of molecular biology, X-ray crystallography, time-resolved FTIR spectroscopy and biomolecular simulations. This combination shows the dynamic processes in the protein after light excitation with atomic resolution. “You can track how the proton is transported from the central proton binding site inside the protein via an amino acid and then via a protonated water cluster to the membrane surface”, says Prof. Gerwert. The interdisciplinary approach is now expanding the classical methods of structural biology, X-ray crystallography and nuclear magnetic resonance spectroscopy (NMR), as it provides a complete film and not just fixed images of proteins. The experiments in Bochum were supplemented by computer simulations in Shanghai. Klaus Gerwert is both a professor at the RUB and Director of the Max Planck Partner Institute for Computational Biology in Shanghai.
Wolf, S., Freier, E., Potschies, M., Hofmann, E. and Gerwert, K.: “Directional Proton Transfer in Membrane Proteins Achieved through Protonated Protein-Bound Water Molecules: A Proton Diode” Angewandte Chemie International Edition, DOI: 10.1002/anie.201001243
Garczarek, F., Gerwert, K.: “Functional waters in intraprotein proton transfer monitored by FTIR difference spectroscopy”. In: Nature 439, 109-112 (2006)
Prof. Dr. Klaus Gerwert, Chair of Biophysics at the Ruhr-Universität Bochum, 44780 Bochum, ND 04/596, Tel. 0234/32-24461, firstname.lastname@example.org
Editor: Meike Drießen
Dr. Josef König | idw
Flow of cerebrospinal fluid regulates neural stem cell division
21.05.2018 | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt
Chemists at FAU successfully demonstrate imine hydrogenation with inexpensive main group metal
21.05.2018 | Friedrich-Alexander-Universität Erlangen-Nürnberg
So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics
Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...
The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...
A team led by Austrian experimental physicist Rainer Blatt has succeeded in characterizing the quantum entanglement of two spatially separated atoms by observing their light emission. This fundamental demonstration could lead to the development of highly sensitive optical gradiometers for the precise measurement of the gravitational field or the earth's magnetic field.
The age of quantum technology has long been heralded. Decades of research into the quantum world have led to the development of methods that make it possible...
Cardiovascular tissue engineering aims to treat heart disease with prostheses that grow and regenerate. Now, researchers from the University of Zurich, the Technical University Eindhoven and the Charité Berlin have successfully implanted regenerative heart valves, designed with the aid of computer simulations, into sheep for the first time.
Producing living tissue or organs based on human cells is one of the main research fields in regenerative medicine. Tissue engineering, which involves growing...
A team of scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg investigated optically-induced superconductivity in the alkali-doped fulleride K3C60under high external pressures. This study allowed, on one hand, to uniquely assess the nature of the transient state as a superconducting phase. In addition, it unveiled the possibility to induce superconductivity in K3C60 at temperatures far above the -170 degrees Celsius hypothesized previously, and rather all the way to room temperature. The paper by Cantaluppi et al has been published in Nature Physics.
Unlike ordinary metals, superconductors have the unique capability of transporting electrical currents without any loss. Nowadays, their technological...
02.05.2018 | Event News
13.04.2018 | Event News
12.04.2018 | Event News
18.05.2018 | Power and Electrical Engineering
18.05.2018 | Information Technology
18.05.2018 | Information Technology