Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

U-Iowa scientists gain insight on how enzyme uses oxygen to produce useful chemicals

14.02.2003


When it comes to visual entertainment, three-dimensional viewing can be quite eye-opening. So, too, in science where a recent finding involving University of Iowa researchers used three-dimensional imaging to understand how a bacterial enzyme can take oxygen from air and use it to convert certain molecules into useful chemicals.



Specifically, the scientists saw that naphthalene dioxygenase, a bacterial enzyme, can bind oxygen (to iron) in a side-on fashion and add it on to naphthalene, a hydrocarbon molecule. The discovery is a result of the first three-dimensional imaging of naphthalene dioxygenase, a member of the family of enzymes called Rieske dioxygenases. The findings could help lead to the development of microorganisms that can clean up toxic and cancer-causing waste in the environment and to the development of novel drugs. The research results appear in the Feb. 14 issue of Science.

"The more we know about how enzymes catalyze reactions, the better able we are to modify them -- to improve or stop reactions, as desired" said S. Ramaswamy, Ph.D., UI professor of biochemistry and one of the study’s authors.


"The question was: how does the enzyme actually work at the molecular level?" said David Gibson, Ph.D., UI professor of microbiology and one of the study’s authors, whose previous research led to the discovery of the Rieske dioxygenase family of enzymes.

That seemingly straightforward question required seven years of collaborative work between the UI and the researchers in Sweden, beginning in 1996, and included assistance from the UI Center for Biocatalysis and Bioprocessing.

Ramaswamy and Gibson began research related to this investigation when Ramaswamy was a faculty member in the molecular biology department at Swedish University of Agricultural Sciences in Uppsala, Sweden. The paper’s lead author is Andreas Karlsson, who was a graduate student of Ramaswamy’s at the Swedish University and currently works for Aventis in Paris.

"People always thought that side-on binding of oxygen to iron existed, but no one had ever seen it in this enzyme or any other catalyst," said Ramaswamy, whose contribution to the project focused on how oxygen specifically binds to iron in the enzyme. Side-on refers to the newly visualized orientation of oxygen as it binds to iron.

The team used X-ray crystallography to determine the three-dimensional structure of the enzyme and then embarked on a series of experiments designed to take snapshots of the enzyme as it catalyzed the reaction, Gibson explained.

In all, the team had to analyze information from nearly 400 crystals in order to focus on five particular snapshots that led to the finding. The approach was revealing.

"Those five three-dimensional snapshots were the most relevant in understanding this side-on mechanism," Ramaswamy said. "Although we could not watch the reaction occur, the snapshots allowed us to see key points of the process."

Gibson likened the improved view to being able to "walk inside a molecule," just as one can walk inside a house and see the layout. By seeing how things are arranged within a molecule, scientists can better predict how to make changes to the structure and thus create desired reactions.

The researchers said the particular finding of their investigation suggests that other oxygen-using enzymes may also use a side-on binding mechanism. Thus, the study approach and results likely will impact how scientists investigate other enzymes of interest.

Scientists use a "lock and key" analogy to describe enzyme actions. In this study, naphthalene dioxygenase (enzyme) is a lock and naphthalene (substrate) is a key. For a reaction to occur between the two, the lock and key need to be complimentary.

"The thought was that there was one key and one lock, but now we are finding out that there can be many keys, or substrates, because we have the ability to go in and make a change to the lock, or enzyme," Gibson said.

"We can use this knowledge to engineer enzymes to do reactions and target other substrates in an effort to create new products or prevent other products from being created," Ramaswamy said.

For example, Gibson said, naphthalene dioxygenase is a key component in the development of the environmentally benign blue dye Indigo. In addition, a related Rieske dioxygenase synthesizes a key precursor in the production of Crixivan, an inhibitor of the AIDS virus.

The research team also included Juanito Parales, UI research assistant in microbiology; Rebecca Parales, Ph.D., UI research scientist in microbiology, and Hans Eklund, Ph.D., a faculty member at Swedish University of Agricultural Sciences.



Funding for the project included National Institutes of Health grants awarded to Ramaswamy and Gibson, a Swedish Research Council for Environment award to Ramaswamy and Eklund and a Swedish Research Council award to Eklund.

STORY SOURCE: University of Iowa Health Science Relations, 5141 Westlawn, Iowa City, Iowa 52242-1178

CONTACT: (media) Becky Soglin, 319-335-6660, becky-soglin@uiowa.edu


Becky Soglin | EurekAlert!
Further information:
http://www.uiowa.edu/

More articles from Life Sciences:

nachricht Symbiotic bacteria: from hitchhiker to beetle bodyguard
28.04.2017 | Johannes Gutenberg-Universität Mainz

nachricht Nose2Brain – Better Therapy for Multiple Sclerosis
28.04.2017 | Fraunhofer-Institut für Grenzflächen- und Bioverfahrenstechnik IGB

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Fighting drug resistant tuberculosis – InfectoGnostics meets MYCO-NET² partners in Peru

28.04.2017 | Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

 
Latest News

Wireless power can drive tiny electronic devices in the GI tract

28.04.2017 | Medical Engineering

Ice cave in Transylvania yields window into region's past

28.04.2017 | Earth Sciences

Nose2Brain – Better Therapy for Multiple Sclerosis

28.04.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>