(ORDO NEWS) — Scientists have discovered an enzyme that helps methanotrophic bacteria turn methane into methanol, which can then be used in fuel cells.
Methane is considered one of the strongest greenhouse gases, but these bacteria are able to cope with it. Now scientists have found the key to this process.
Methanotrophic bacteria consume 30 million tons of methane per year and have captivated researchers with their natural ability to convert this greenhouse gas into useful compounds.
However, we knew very little about how this complex reaction occurs, which means we could not use this information to create new methods for detecting greenhouse compounds from the atmosphere.
By studying an enzyme that bacteria use to catalyze the reaction, a team at Northwestern University has uncovered key structures that may drive the process. The authors of the work believe that the results obtained can lead to the development of artificial biological catalysts that convert methane to methanol.
How do bacteria convert greenhouse gas into methanol?
An enzyme called dispersed methane oxygenase (pMMO) is a particularly difficult protein to study because it is embedded in the bacterial cell membrane.
Typically, when researchers study these methanotrophic bacteria, they use a process in which proteins are “washed out” of cell membranes using a washing solution. While this procedure effectively isolates the enzyme, it also kills all enzyme activity and limits the amount of information researchers can gather.
In this study, the team used an entirely new technique. The authors placed the enzyme back into a membrane resembling its native environment. They used bacterial lipids to form a membrane inside a protective particle called a nanodisc and then inserted an enzyme into that membrane.
The researchers used cryoelectron microscopy, a technique that allows a good examination of membrane proteins. This enabled them to visualize, for the first time, the atomic structure of an active enzyme at high resolution.
The researchers were able to recreate all the conformations in a computer program and see how they change during catalysis. As a result, scientists now have a greenhouse gas-to-fuel tool that can be improved and put into practice to combat global warming.
Contact us: [email protected]