Surprising behavior of a fatty acid enzyme with potential biofuel applications

Derived from microscopic algae, the rare, light-driven enzyme converts fatty acids into starting ingredients for solvents and fuels.

Although many organisms capture and respond to sunlight, it’s rare to find enzymes – proteins that promote chemical reactions in living things – that are driven by light. Scientists have identified only three so far. The newest one, discovered in 2017, is called fatty acid photodecarboxylase (FAP). Derived from microscopic algae, FAP uses blue light to convert fatty acids into hydrocarbons that are similar to those found in crude oil.

“A growing number of researchers envision using FAPs for green chemistry applications because they can efficiently produce important components of solvents and fuels, including gasoline and jet fuels.” says Martin Weik, the leader of a research group at the Institut de Biologie Structurale at the Université Grenoble Alpes.

Weik is one of the primary investigators in a new study that has captured the complex sequence of structural changes, or photocycle, that FAP undergoes in response to light, which drives this fatty acid transformation. Researchers had proposed a possible FAP photocycle, but the fundamental mechanism was not understood, partly because the process is so fast that it’s very difficult to measure. Specifically, scientists didn’t know how long it took FAP to split a fatty acid and release a hydrocarbon molecule.

Experiments at the Linac Coherent Light Source (LCLS) at the Department of Energy’s SLAC National Accelerator Laboratory helped answer many of these outstanding questions. The researchers described their results in Science.

Read more on the SLAC website

Image: A study using SLAC’s LCLS X-ray laser captured how light drives a series of complex structural changes in an enzyme called FAP, which catalyzes the transformation of fatty acids into starting ingredients for solvents and fuels. This drawing captures the starting state of the catalytic reaction. The dark green background represents the protein’s molecular structure. The enzyme’s light-sensing part, called the FAD cofactor, is shown at center right with its three rings absorbing a photon coming from bottom left. A fatty acid at upper left awaits transformation. The amino acid shown at middle left plays an important role in the catalytic cycle, and the red dot near the center is a water molecule.

Credit: Damien Sorigué/Université Aix-Marseille

Science Begins at Brookhaven Lab’s New Cryo-EM Research Facility

Brookhaven Lab’s Laboratory for BioMolecular Structure is now open for experiments with visiting researchers using two NY State-funded cryo-electron microscopes.

UPTON, NY—On January 8, 2021, the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory welcomed the first virtually visiting researchers to the Laboratory for BioMolecular Structure (LBMS), a new cryo-electron microscopy facility. DOE’s Office of Science funds operations at this new national resource, while funding for the initial construction and instrument costs was provided by NY State. This state-of-the-art research center for life sciences imaging offers researchers access to advanced cryo-electron microscopes (cryo-EM) for studying complex proteins as well as the architecture of cells and tissues.

Many modern advances in biology, medicine, and biotechnology were made possible by researchers learning how biological structures such as proteins, tissues, and cells interact with each other. But to truly reveal their function as well as the role they play in diseases, scientists need to visualize these structures at the atomic level. By creating high-resolution images of biological structure using cryo-EMs, researchers can accelerate advances in many fields including drug discovery, biofuel development, and medical treatments.

Read more on the BNL website

Image: Brookhaven Lab Scientist Guobin Hu loaded the samples sent from researchers at Baylor College of Medicine into the new cryo-EM at LBMS.

Converting emissions into valuable fuel

Researchers used the Canadian Light Source (CLS) at the University of Saskatchewan to improve their technique to convert CO2 into ethanol, a valuable chemical that can be used in a variety of industrial applications. Ethanol is also an attractive alternative fuel.

Ethanol has been proven to reduce emissions when compared to gasoline, but the renewable fuel is most often made of corn and wheat so there is a strong interest in non-food production methods. By capturing and converting carbon emissions to ethanol, the fuel’s environmental benefits could be multiplied.

The research team led by Prof. Ted Sargent at the University of Toronto focused on producing chemicals through CO2 conversion—such as ethanol, ethylene and methane—helping to transform harmful greenhouse gases into useful products. The group aims to produce the target chemicals, in this case ethanol, with high outputs and minimal energy inputs.

Read more on the Canadian Light Source website

Image: Xue Wang installing a membrane electrode assembly MEA cell for testing the performance of the N-CCu catalyst in CO2RR.