Researchers discover that a spot of molecular glue and a timely twist help a bacterial enzyme convert carbon dioxide into carbon compounds 20 times faster than plant enzymes do during photosynthesis. The results stand to accelerate progress toward converting carbon dioxide into a variety of products.
Plants rely on a process called carbon fixation – turning carbon dioxide from the air into carbon-rich biomolecules – for their very existence. That’s the whole point of photosynthesis, and a cornerstone of the vast interlocking system that cycles carbon through plants, animals, microbes and the atmosphere to sustain life on Earth.
But the carbon fixing champs are not plants, but soil bacteria. Some bacterial enzymes carry out a key step in carbon fixation 20 times faster than plant enzymes do, and figuring out how they do this could help scientists develop forms of artificial photosynthesis to convert the greenhouse gas into fuels, fertilizers, antibiotics and other products.
Now a team of researchers from the Department of Energy’s SLAC National Accelerator Laboratory, Stanford University, Max Planck Institute for Terrestrial Microbiology in Germany, DOE’s Joint Genome Institute (JGI) and the University of Concepción in Chile has discovered how a bacterial enzyme – a molecular machine that facilitates chemical reactions – revs up to perform this feat.
Rather than grabbing carbon dioxide molecules and attaching them to biomolecules one at a time, they found, this enzyme consists of pairs of molecules that work in sync, like the hands of a juggler who simultaneously tosses and catches balls, to get the job done faster. One member of each enzyme pair opens wide to catch a set of reaction ingredients while the other closes over its captured ingredients and carries out the carbon-fixing reaction; then, they switch roles in a continual cycle.
Read more on the SLAC website