Alternative Fuel and Hybrid Market to Propel Forward as Researchers Uncovered Crucial Structures that can Convert Methane Gas into Methanol
Posted On April 16, 2022
Methanotrophic bacteria consume 30 million metric tonnes of methane per year. It has a natural capacity to transform the potent greenhouse gas into useable fuel has enthralled experts. However, little is known about how the complex interaction occurs, restricting researchers' ability to take advantage of the twofold benefit.
Northwestern University researchers have now uncovered crucial structures that may drive the process. This was done by analysing the enzyme used by bacteria to catalyse the reaction. Their discoveries are highly relevant for the Alternative Fuel and Hybrid Market as they could eventually develop artificial biological catalysts that convert methane gas to methanol.
Since methane has a solid bond, it is astonishing that an enzyme can achieve this. The development and enhancement of the enzymes for biotechnological uses can only occur when we understand precisely how it does this challenging process occur.
The enzyme particulate methane monooxygenase (pMMO) is a complex protein to investigate because it is lodged in the bacteria's cell membrane. When studying these methanotrophic bacteria, researchers typically use a severe technique. Therein, the proteins are pulled out of the cell membranes using a detergent solution. While this approach effectively isolates the enzyme, it also kills all enzyme activity and limits the amount of information researchers can gather – similar to monitoring a heart without a heartbeat.
Researchers wondered if they could learn something new by reintroducing the enzyme into a membrane that resembled its native environment. The team employed bacterial lipids to create a membrane within a protective particle known as a nanodisc and then implanted the enzyme within that membrane.
The team observed they could restore enzyme function by replicating the enzyme's original environment within the nanodisc. Further, they were then able to employ structural tools to understand how the lipid bilayer restored activity at the atomic level. As a result, the group uncovered the complete configuration of the copper site in the enzyme where methane oxidation is most likely to occur.
The researchers utilised Cryo-electron microscopy (cryo-EM) since the lipid membrane environment was not disrupted during the experiment. For first ever, they were able to see the atomic structure of the active enzyme at excellent resolution.
Cryo-EM structures provide a new starting point for answering the questions piling up. The researchers intend to analyse the enzyme directly within the bacterial cell using cryo-electron tomography (cryo-ET), a cutting-edge imaging technology.
If the researchers are successful, they will be able to examine how the enzyme is structured in the cell membrane. They can note how it acts in its proper native context and whether other proteins around the enzyme interact with it. These findings would provide a critical missing link to engineers.