Featured Research

from universities, journals, and other organizations

Researchers discover proton diode: Water is an active element in proteins

Date:
September 3, 2010
Source:
Ruhr-Universitaet-Bochum
Summary:
Biophysicists in Germany 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 were able to observe this through a combination of molecular biology, X-ray crystallography, time-resolved FTIR spectroscopy and biomolecular simulations.

The proton diode in the light-driven proton pump bacteriorhodopsin.
Credit: Image courtesy of Ruhr-Universitaet-Bochum

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.

Related Articles


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."

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.


Story Source:

The above story is based on materials provided by Ruhr-Universitaet-Bochum. Note: Materials may be edited for content and length.


Journal References:

  1. Steffen Wolf, Erik Freier, Meike Potschies, Eckhard Hofmann, Klaus Gerwert. Directional Proton Transfer in Membrane Proteins Achieved through Protonated Protein-Bound Water Molecules: A Proton Diode. Angewandte Chemie International Edition, 2010; DOI: 10.1002/anie.201001243
  2. Florian Garczarek, Klaus Gerwert. Functional waters in intraprotein proton transfer monitored by FTIR difference spectroscopy. Nature, 2005; 439 (7072): 109 DOI: 10.1038/nature04231

Cite This Page:

Ruhr-Universitaet-Bochum. "Researchers discover proton diode: Water is an active element in proteins." ScienceDaily. ScienceDaily, 3 September 2010. <www.sciencedaily.com/releases/2010/09/100902073643.htm>.
Ruhr-Universitaet-Bochum. (2010, September 3). Researchers discover proton diode: Water is an active element in proteins. ScienceDaily. Retrieved December 19, 2014 from www.sciencedaily.com/releases/2010/09/100902073643.htm
Ruhr-Universitaet-Bochum. "Researchers discover proton diode: Water is an active element in proteins." ScienceDaily. www.sciencedaily.com/releases/2010/09/100902073643.htm (accessed December 19, 2014).

Share This


More From ScienceDaily



More Matter & Energy News

Friday, December 19, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Building Google Into Cars

Building Google Into Cars

Reuters - Business Video Online (Dec. 19, 2014) Google's next Android version could become the standard that'll power your vehicle's entertainment and navigation features, Reuters has learned. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
AP Review: Nikon D750 and GoPro Hero 4

AP Review: Nikon D750 and GoPro Hero 4

AP (Dec. 19, 2014) What to buy an experienced photographer or video shooter? There is some strong gear on the market from Nikon and GoPro. The AP's Ron Harris takes a closer look. (Dec. 19) Video provided by AP
Powered by NewsLook.com
Navy Unveils Robot Fish

Navy Unveils Robot Fish

Reuters - Light News Video Online (Dec. 18, 2014) The U.S. Navy unveils an underwater device that mimics the movement of a fish. Tara Cleary reports. Video provided by Reuters
Powered by NewsLook.com
3D Printed Cookies Just in Time for Christmas

3D Printed Cookies Just in Time for Christmas

Reuters - Innovations Video Online (Dec. 18, 2014) A tech company in Spain have combined technology with cuisine to develop the 'Foodini', a 3D printer designed to print the perfect cookie for Santa. Ben Gruber reports. Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins