How bacteria build an enzyme that destroys laughing gas that changes the climate



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New research from the University of East Anglia reveals how soil bacteria build the only enzyme known to destroy potent global warming and gaseous nitrous oxide that destroys the ozone layer.

Together with carbon dioxide (CO2) and methane, nitrous oxide (N2O) of greenhouse gases, commonly known as "gas of laughter", is now cause for great concern, and there is much focus reduction of emissions.

It is hoped that the results, published today in the journal Chemical Science, will help pave the way for strategies to mitigate the damaging effects of this gas that changes the climate.

N2O has about 300 times the global warming potential of CO2 and remains in the atmosphere for about 120 years, accounting for about nine percent of total greenhouse gases.

It also destroys the ozone layer with potency similar to the currently banned chlorofluorocarbons (CFCs).

Atmospheric levels of N2O increase year after year as microorganisms destroy synthetic nitrogen fertilizers that are added to agricultural land to meet the food supply demands of a growing global population.

Nick Le Brun of the UEA's Chemistry School said: "It is well known that some bacteria can" breathe "N2O in environments where oxygen (O2) is limited.

"This ability is totally dependent on an enzyme called nitrous oxide reductase, which is the only enzyme known to destroy N2O, so it is very important to control the levels of this gas that changes the climate.

"We wanted to know more about how soil bacteria use this enzyme to destroy nitrous oxide."

The part of the enzyme where N2O is consumed (called the active site & # 39;) is unique in biology, consisting of a complex arrangement of copper and sulfur (a cluster of copper sulphide). So far, the knowledge of how this unusual active site is built by bacteria is lacking.

The UEA team discovered a protein called NosL, which is needed to mount the active site of the copper sulfide cluster and activates the enzyme.

They found that bacteria without NosL still produced the enzyme but contained less of the active site of copper sulphide. In addition, when the same bacteria were cultured with missing copper, the active site was completely absent from the enzyme.

The team also showed that NosL is a copper binding protein, indicating that it works directly in supplying copper for the assembly of the active site of the copper sulfide cluster.

Prof Le Brun said: "The discovery of the function of NosL is the first step in understanding how the only active site of nitrous oxide reductase is assembled. This is fundamental information because when the assembly goes wrong, the inactive enzyme leads to the release of N2O in the atmosphere. "

The UEA team was led by Prof Nick Le Brun and Dr. Andy Gates of the UEA School of Life Sciences, and included the Vice-Rector of the University, Prof. David Richardson – also of the School of Biological Sciences. They are part of the EU's international network, focused on understanding different aspects of N2O and the nitrogen cycle.

Dr. Gates said: "Society is well aware of the need to address carbon dioxide emissions, but nitrous oxide is emerging as an urgent global concern and requires researchers with different skills to work together to avoid further damaging effects of change climate change.

"With increasing understanding of the enzymes that produce and destroy N2O, we are approaching to develop strategies to mitigate the harmful effects of this climate-altering gas on Earth's environment."

Study reveals how soil bacteria are prepared to consume greenhouse gas

More information:
& # 39; NosL is a dedicated copper escort for the assembly of the nitrous oxide reductase center Cuz & # 39; is published in Chemical Science, a peer-reviewed journal published by the Royal Society of Chemistry on April 18, 2019.… c01053j #! divAbstract

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University of East Anglia

How bacteria build an enzyme that destroys the laughing gas that changes the climate (2019, April 18)
recovered April 18, 2019

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