It’s all about those enzymes.
Enzymes are nature’s magicians. They perform incredibly complicated feats of chemistry in milliseconds. They change light and food into energy, carbon dioxide into oxygen, one cell into two. They are responsible for catalyzing — speeding up — every biological process. If researchers could replicate the power, speed and efficiency of nature’s enzymes, it could mean true renewable energy, not to mention new drugs and greener industrial materials.
There has been some progress in engineering enzymes — think ethanol and other biofuel fuels — but enzymes designed in a lab still can’t compete with those evolved in nature. This is partly because researchers haven’t had a clear, step-by-step understanding of how enzymes do their magic.
Now, we do.
For the first time, Brandeis University researchers have observed and recorded each step of how the enzyme adenylate kinase (ADK), catalyzes the transfer of energy in our cells. Dorothee Kern, professor of biochemistry and Howard Hughes Medical Institute Investigator, published the findings in a recent issue of Nature Structural and Molecular Biology.
ADK plays an important role in cellular energy homeostasis, maintaining the right nucleotide (chemical energy storage molecules) levels in cells. Kern and her team, which included professor Michael Hagan, outlined the minimum five-step process of catalysis, during which the sophisticated ADK enzyme binds the target nucleotides, closes around them, catalyzes the chemical reaction, reopens and releases the final product. The whole process takes milliseconds with the enzyme. Without it, it would take about 8,000 years for this process to happen naturally.
The team also observed what each part of the enzyme does during the process — revealing an efficient team of players, including magnesium, each responsible for multiple parts of catalysis.
“We found that you really can’t get much more efficient than ADK,” Kern says. “It really is an amazing accelerator.”
Kern’s work is a first step to designing better, faster, stronger enzymes but there is still a long way to go.
“The first step is seeing how it works in nature,” Kern says. “Then, we can figure out how to make it better.”
This work was supported by the Howard Hughes Medical Institute, the Office of Basic Energy Sciences, Catalysis Science Program, Department of Energy and the National Institutes of Health.