Featured Research

from universities, journals, and other organizations

Why oxygen becomes the undoing of proteins

Date:
November 7, 2011
Source:
Ruhr-Universitaet-Bochum
Summary:
Scientists have published a new study explaining why enzymes used for the production of hydrogen are so sensitive to oxygen. They used spectroscopic methods to investigate the time course of the processes that lead to the inactivation of the enzyme's iron center.

Scientists from the Faculty of Biology and Biotechnology at the RUB have published a report in the Journal of Biological Chemistry explaining why enzymes used for the production of hydrogen are so sensitive to oxygen. In collaboration with researchers from Berlin, they used spectroscopic methods to investigate the time course of the processes that lead to the inactivation of the enzyme's iron center.

Related Articles


"Such enzymes, the so-called hydrogenases, could be extremely significant for the production of hydrogen with the help of biological or chemical catalysts," explains Camilla Lambertz from the RUB study group for photobiotechnology. "Their extreme sensitivity to oxygen is however a major problem. In future, our results could help to develop enzymes that are more robust."

Oxygen as a friend and as an enemy

Oxygen is crucial for the survival of most animals and plants. It is however toxic for many living creatures if the concentration thereof is too high, and some organisms can even only exist entirely without oxygen. Sensitivity to oxygen is also present at the protein level. A large number of enzymes, for example, hydrogenases are known to be irreversibly destroyed by oxygen. Hydrogenases are biological catalysts that convert protons and electrons into technically usable hydrogen. The RUB team of Prof. Thomas Happe is doing research on so-called [FeFe]-hydrogenases which are capable of producing particularly large amounts of hydrogen. The generation of hydrogen takes place at the H-cluster, consisting of a di-iron and four-iron subcluster which, together with other ligands, form the reactive center.

Oxygen attacks the iron centers

The researchers, working in collaboration with Dr. Michael Haumann's team in Berlin, discovered that oxygen binds to the di-iron center of the hydrogenase, which initiates the inactivation of another part of the enzyme consisting of four further iron atoms. In this project, sponsored by the BMBF, it was possible to show the diverse phases of the inactivation process for the first time using the so-called X-ray absorption spectroscopy. The researchers used the synchroton radiation source Swiss Light Source in Switzerland for this specific type of measurement. It generates particularly strong rays, thus enabling the characterization of metal centers in proteins. Amongst other things, the scientists thus determined the chemical nature of the iron centers and the distance from the surrounding atoms using atomic resolution.

Inactivation in three phases

The team of researchers from Bochum and Berlin used a new experimental procedure. They initially brought the hydrogenase sample into contact with oxygen for a few seconds to minutes and finally for a couple of hours and then suppressed all proceeding reactions by deep-freezing it in liquid nitrogen. The subsequently gained spectroscopic data was used for the development of a model for a three-phase inactivation process. According to this model, an oxygen molecule initially binds to the di-iron center of the hydrogenase, which leads to the development of an aggressive oxygen species. In the subsequent phase, this attacks and modifies the four-iron center. During the final phase, further oxygen molecules bind and the entire complex disintegrates.

"The entire process thus consists of a number of consecutive reactions that are distinctly separated in time," says Lambertz. "The velocity of the entire process is possibly dependent on the phase during which the aggressive oxygen species moves from the di-iron to the four-iron center. We are currently elaborating further experiments to investigate this."


Story Source:

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


Journal Reference:

  1. C. Lambertz, N. Leidel, K. G. V. Havelius, J. Noth, P. Chernev, M. Winkler, T. Happe, M. Haumann. O2-reactions at the six-iron activesite (H-cluster) in [FeFe]-hydrogenase. Journal of Biological Chemistry, 2011; DOI: 10.1074/jbc.M111.283648

Cite This Page:

Ruhr-Universitaet-Bochum. "Why oxygen becomes the undoing of proteins." ScienceDaily. ScienceDaily, 7 November 2011. <www.sciencedaily.com/releases/2011/10/111012083448.htm>.
Ruhr-Universitaet-Bochum. (2011, November 7). Why oxygen becomes the undoing of proteins. ScienceDaily. Retrieved March 30, 2015 from www.sciencedaily.com/releases/2011/10/111012083448.htm
Ruhr-Universitaet-Bochum. "Why oxygen becomes the undoing of proteins." ScienceDaily. www.sciencedaily.com/releases/2011/10/111012083448.htm (accessed March 30, 2015).

Share This


More From ScienceDaily



More Matter & Energy News

Monday, March 30, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Inspectors Found Faulty Work Before NYC Blast

Inspectors Found Faulty Work Before NYC Blast

AP (Mar. 27, 2015) An hour before an apparent gas explosion sent flames soaring and debris flying at a Manhattan apartment building, injuring 19 people, utility company inspectors decided the work being done there was faulty. (March 27) Video provided by AP
Powered by NewsLook.com
Facebook Building Plane-Sized Drones For Global Internet

Facebook Building Plane-Sized Drones For Global Internet

Newsy (Mar. 27, 2015) Facebook on Thursday revealed more details about its Internet-connected drone project. The drone is bigger than a 737, but lighter than a car. Video provided by Newsy
Powered by NewsLook.com
Robot Returns from International Space Station and Sets Two Guinness World Records

Robot Returns from International Space Station and Sets Two Guinness World Records

Reuters - Light News Video Online (Mar. 27, 2015) The companion robot "Kirobo" returns to earth from the International Space Station and sets two Guinness World Records. Sharon Reich reports. Video provided by Reuters
Powered by NewsLook.com
Residents Witness Building Explosion, Collapse

Residents Witness Building Explosion, Collapse

AP (Mar. 26, 2015) Witnesses recount the sites and sounds of a massive explosion and subsequent building collapse in the heart of Manhattan&apos;s trendy East Village on Thursday. (March 26) Video provided by AP
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