Nitrogen fixing enzyme also produces hydrocarbons, finds new study

Nitrogen fixing enzyme also produces hydrocarbons, finds new study

7:01 AM, 27th September 2014
Nitrogen fixing enzyme also produces hydrocarbons, finds new study
Einsle and his team developed this new crystal structure of the metal core of the nitrogenase. It demonstrates how carbon monoxide (CO) while it is binding to a hydrogen molecule, dislocates a sulfure atome.

FREIBURG, GERMANY: Plants need nitrogen and carbon to grow. Photosynthesis allows them to take in the latter directly from the air, but they have to procure nitrogen through their roots in the form of organic molecules like ammonia or urea. Even though nitrogen gas makes up approximately 80 per cent of Earth’s atmosphere, the plant can only access it in a bound – or ‘fixed’ – form. Farmers thus use fertilizers to provide their crops with nitrogen. The only living beings that can convert nitrogen from the air into usable molecules are microorganisms – for example nodule bacteria. They possess the enzyme nitrogenase, which combines nitrogen with hydrogen to form ammonium. In a new study, Professor Dr Oliver Einsle and Dr Thomas Spatzal have not just contributed to the further elucidation of how this enzyme functions, but also described a unique mechanism it uses to produce hydrocarbons. “We want to understand the reactions of nitrogenase in order to make the enzyme available for future biotechnological applications. At present, half of humankind can only be fed through the use of fertilizers in agriculture. This consumes roughly one per cent of the world’s energy production,” explained Einsle.

The researchers demonstrated for the first time how nitrogenase converts carbon monoxide. This leads to the production of molecules that resemble biofuels. “Thus, the enzyme is also interesting for sustainable energy production,” said Einsle.

Einsle is studying the microstructure of the heart of the enzyme: a large metal core called the iron molybdenum cofactor (FeMoco). Einsle, Spatzal, and Prof. Dr Douglas Rees in Pasadena, USA, have obtained a crystal structure that shows how a carbon monoxide molecule (CO) binds to FeMoco. “There, it unexpectedly pushes away a sulfur atom that had previously occupied the same position in the metal core. For the first time, this allows us to draw inferences on how the core reacts with other molecules,” described Einsle. The researchers published their findings in the journal Science.

“A chemical rearrangement of this kind has never been observed before in a biological system,” explained Einsle. It has been known since 2010 that CO, an inhibitor of nitrogenase, is slowly converted to hydrocarbons to a minimal extent. By applying CO gas to the enzyme during the nitrogenase reaction, the researchers found a binding site for CO and succeeded in documenting the rearrangement. Thus, in addition to the so-called “Haber-Bosch process of nitrogen fixation,” nitrogenase also stimulates a reaction corresponding to the “Fischer-Tropsch synthesis of hydrocarbons,” which can be used on a large scale to synthesize fuels, for instance from industrial waste gases. “The new structural analysis is the first ever description of the mechanism of this unusual reactivity,” said Einsle.

Oliver Einsle serves as professor at the Institute of Biochemistry of the University of Freiburg and is a member of the Cluster of Excellence BIOSS Centre for Biological Signalling Studies of the University of Freiburg. Thomas Spatzal completed his dissertation in Freiburg and is now conducting research with Douglas Rees at the California Institute of Technology in Pasadena, US.

© University of Freiburg News



Your Comments (Up to 2000 characters)
Please respect our community and the integrity of its participants. WOC reserves the right to moderate and approve your comment.

Related News

EU restricts use of three preservatives in cosmetic products

BRUSSELS, BELGIUM: The European Union (EU) has adopted two measures restricting the use of three preservatives in cosmetic products. The Commission to ...

Read more
Maverick Synfuels introduces small-scale methane-to-methanol production plant

RESEARCH TRIANGLE PARK, US: Maverick Synfuels, a leader in alternative chemicals and fuels production technology, introduced the first small-scale, mo ...

Read more
Harcros Chemicals fined $1.5 million for storing hazardous waste

KANSAS CITY, US: Harcros Chemicals, a Kansas chemical company, has been fined $1.5 million after pleading guilty for storing hazardous waste without a ...

Read more
Inexpensive, simple way to make transparent, flexible transistors

WASHINGTON DC, US: As tech company LG demonstrated the unveiling of its 18-inch flexible screen, the next generation of roll-up displays is tantalizin ...

Read more
PPG opens regional headquarters for architectural coatings

PITTSBURGH, US: PPG Industries marked the opening of a regional headquarters for its architectural coatings business in the US, Canada and Puerto Rico ...

Read more
Lanxess expands production capacity in Brilon, Germany

BRILON, GERMANY: Lanxess subsidiary, Bond-Laminates, that belongs to the business unit High Performance Materials, has completed capacity expansion at ...

Read more uses cookies to ensure that we give you the best experience on our website. By using this site, you agree to our Privacy Policy and our Terms of Use. X