Scientists replicate enzyme that captures carbon

Researchers at King’s College London have recreated the active site of acetyl-CoA synthase, an enzyme involved in sequestering carbon from the atmosphere. Research carried out in collaboration with Imperial College London advances our understanding of this important enzyme and offers a potential new solution for CO capture.₂ from the atmosphere in the fight against climate change.

The team led by Dr. Rebecca Musgrave from the Department of Chemistry and Dr. UCL’s Daniel Wilson has successfully recreated the active site – the place where chemical reactions take place – of the enzyme Acetyl-CoA synthase (ACS).

ACS transforms CO₂ to acetyl coenzyme-A – an essential molecule used by living beings. Their findings are published in Journal of the American Chemical Society.

ACS is best known for its role in the acetic acid cycle, or Krebs cycle, a series of chemical reactions in living things in which acetic acid is oxidized to produce energy. It is therefore vital for energy storage and release and for CO capture₂ from the atmosphere and is stored as carbon.

The team’s new model was able to replicate this chemical reaction in the lab, capturing atmospheric carbon and storing it as acetyl coenzyme-A.

Enzymes are proteins that act as biological catalysts by speeding up chemical reactions. As such, they perform vital functions in nature, including human biology.

The chemical pathways created by enzymes have evolved over billions of years into large, complex biological systems, making them very challenging to study and replicate in the laboratory. Scientists often create smaller molecular versions of enzymes—“active site” models—in the laboratory to study them.

The ACS enzyme is found in bacteria and some single-celled organisms and works without oxygen to create complex organic molecules from carbon dioxide and hydrogen. While attempts have been made to model the active site of the enzyme in the laboratory, they have not been able to accurately replicate the shape and electronic environment of the carbon capture active site.

Dr. Daniel Wilson, lead researcher from UCL, said: “Scientists have studied the enzyme ACS for decades, but the mechanism that produces acetyl coenzyme-A in the active site of the enzyme has been difficult to decipher. In our study, we present a model of the active site – a molecular cluster containing two nickel atoms – which mimics the shape and size with remarkable similarity to the active site of the ACS enzyme.

“Excitingly, exposing our model to carbon monoxide led to a successful synthesis, mimicking the way the ACS enzyme creates acetyl Co-A in nature.”

In collaboration with Dr. Imperial’s Maxie Roessler and the team used a technique called Electron Paramagnetic Spectroscopy to study the steps involved and believe the results will provide valuable insight to scientists studying the ACS enzyme – and other enzymes related to atmospheric carbon fixation, or carbon capture. .

Dr. Rebecca Musgrave said: “Our new model opens the way to a better understanding of how this reaction works. By studying individual reaction steps using electron paramagnetic resonance spectroscopy and other techniques, we can use what we learn to inform the design of artificial catalysts for industrial use.

“This could be applied in a number of areas, including new methods for capturing CO₂ from the atmosphere and use it as a feedstock to make carbon-based chemicals such as biofuels for cars or pharmaceuticals.”

The researchers also hope that those working in enzyme spectroscopy—the branch of enzyme study—will be able to take their new model and adapt it for use in their own studies.

Dr. Musgrave said: “Enzymes in nature carry out these incredible transformations so quickly and efficiently, in a way that is very difficult to reproduce in the laboratory. Our new model brings us one step closer to understanding how these biological systems do it so well.” , so we can design industrial-scale catalysts to replicate nature’s transformative power and address key societal issues such as climate change.”