Probing hydrogen catalyst assembly

Jan 23, 2014

Biochemical reactions sometimes have to handle dangerous things in a safe way. New work from researchers at UC Davis and Stanford University shows how cyanide and carbon monoxide are safely bound to an iron atom to construct an enzyme that can generate hydrogen gas. The work is published Jan. 24 in the journal Science.

Producing hydrogen with catalysts based on abundant metals, such as iron, is key to hopes of using hydrogen to replace carbon-based fuels. But before you can make hydrogen, you have to make the catalyst that enables the reaction –something bacteria have been able to do for millennia.

Jon Kuchenreuther, a postdoctoral researcher working with Professor Dave Britt, project scientist Simon George and colleagues at the UC Davis Department of Chemistry, with James Swartz and colleagues at Stanford, used a variety of analysis techniques to study the chain of chemical reactions that assembles these catalysts based on clusters of iron and adorned with cyanide (CN) and (CO) molecules.

"How does biology make these complicated active sites?" Britt said. "You can't release cyanide or carbon monoxide into the cell. It turns out that it's formed and kept on iron throughout."

In work published in Science last year, the researchers showed that the first binds to the iron/sulfur cluster, and is then split by the enzyme HydG to create a radical. The new paper picks up the story from there, showing that carbon monoxide and cyanide derived from the splitting of tyrosine, remain bound to the same as the tyrosine radical is removed. This iron/cyanide/carbon monoxide structure becomes part of the final cluster.

This video is not supported by your browser at this time.
Inexpensive catalysts for forming hydrogen would boost alternative fuels. UC Davis chemist Dave Britt talks about work to understand how such catalysts are assembled in nature. Credit: Produced by Andy Fell, UC Davis.

The team principally used a technique called Fourier Transform Infra Red spectroscopy to follow the process. FTIR measures vibrations in bond length, and both cyanide and carbon monoxide show strong signals with this method.

Metal atoms in biological molecules are usually bound to large structures, like amino acids or heme groups, Britt said. For metals to be bound to small molecules, like carbon monoxide and cyanide, is "some unusual chemistry by itself," he said.

Explore further: Unique chemistry in hydrogen catalysts

More information: "The HydG Enzyme Generates an Fe(CO)2(CN) Synthon in Assembly of the FeFe Hydrogenase H-Cluster" Science, 2014.

Related Stories

Unique chemistry in hydrogen catalysts

Oct 24, 2013

Making hydrogen easily and cheaply is a dream goal for clean, sustainable energy. Bacteria have been doing exactly that for billions of years, and now chemists at the University of California, Davis, and Stanford University ...

Cheap metals can be used to make products from petroleum

Oct 21, 2013

The ancient alchemists sought to transform base metals, like lead, into precious gold. Now a new process developed at the University of Illinois at Chicago suggests that base metals may be worth more than their weight in ...

New method for producing clean hydrogen

May 21, 2013

Duke University engineers have developed a novel method for producing clean hydrogen, which could prove essential to weaning society off of fossil fuels and their environmental implications.

New antidote for smoke-related cyanide toxicity shows promise

Oct 22, 2012

Smoke inhalation is the major cause of death in fire victims due to cyanide poisoning. However, new research presented at CHEST 2012, the annual meeting of the American College of Chest Physicians, shows that a new antidote, ...

The dance of the atoms

Jun 10, 2013

( —Catalysts can stop working when atoms on the surface start moving. At the Vienna University of Technology, this dance of the atoms could now be observed and explained.

Recommended for you

A greener source of polyester—cork trees

Apr 16, 2014

On the scale of earth-friendly materials, you'd be hard pressed to find two that are farther apart than polyester (not at all) and cork (very). In an unexpected twist, however, scientists are figuring out ...

A beautiful, peculiar molecule

Apr 16, 2014

"Carbon is peculiar," said Nobel laureate Sir Harold Kroto. "More peculiar than you think." He was speaking to a standing-room-only audience that filled the Raytheon Amphitheater on Monday afternoon for the ...

Metals go from strength to strength

Apr 15, 2014

To the human hand, metal feels hard, but at the nanoscale it is surprisingly malleable. Push a lump of metal with brute force through a right-angle mould or die, and while it might look much the same to the ...

User comments : 0

More news stories

Better thermal-imaging lens from waste sulfur

Sulfur left over from refining fossil fuels can be transformed into cheap, lightweight, plastic lenses for infrared devices, including night-vision goggles, a University of Arizona-led international team ...

Hackathon team's GoogolPlex gives Siri extra powers

( —Four freshmen at the University of Pennsylvania have taken Apple's personal assistant Siri to behave as a graduate-level executive assistant which, when asked, is capable of adjusting the temperature ...

Chronic inflammation linked to 'high-grade' prostate cancer

Men who show signs of chronic inflammation in non-cancerous prostate tissue may have nearly twice the risk of actually having prostate cancer than those with no inflammation, according to results of a new study led by researchers ...