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One "Cool Tool" That's Helping Repair Your DNA

April 18, 2011 - 1:20pm


With the arrival of spring, many families are dusting off their tools to make some home improvements. It’s worth remembering that nature also has some pretty cool tools as well.

Specifically, researchers at the Energy Department’s Lawrence Berkeley Lab and their collaborators recently discovered a new, flexible tool that cells use to perform the essential function of repairing damaged DNA.

Berkeley scientists used a cool tool of their own, the Advanced Light Source – which produces X-ray light that shines a billion times brighter than the sun – to study the structure of a DNA repair machine called MRN (also known as Mre11-Rad50-Nbs1), and specifically, the attachment point for its two main components. To their surprise, scientists discovered that the motor that drives the actual repair (Rad50) is tethered to the rest of the machine in a fairly flexible fashion.

Cellular tools, which are typically made up of proteins, aren’t supposed to look like that. They are thought to fit fairly closely and specifically to whatever they might be working on, more like a lock-and-key than a bungee cord.

But Berkeley scientists showed that the unexpected flexibility of MRN allows it to function like a pair of pliers, with jaws that can twist and turn to fit the size of whatever job is needed. MRN sets into place, and then Rad50 snaps shut as the repair begins, providing the energy to power the job.

Scientists have begun taking a closer look at flexible and even unstructured proteins (see April’s issue of Scientific American), since they are thought to be important in a wide range of processes, and understanding how they work might lead to new disease targets and new helpful medicines.

Further insight into MRN and other DNA repair machines may also give scientists new insights into fighting some cancers as well as other diseases such as cystic fibrosis. While the Department does the majority of its work in the physical sciences, its scientists could well play a role in future studies in this area, since they have powerful and sensitive tools – such as the Advanced Light Source – which allows them to examine everything from the structure of proteins to the chemistry of the ozone layer.

While these cool tools from the Office of Science won’t help you change the oil or clean the yard, they can have a big impact on our world.

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