The scientists from The Scripps Research Institute have used this information to design drug candidates with potential to counter those defects and reverse the disease.
"This the first time the structure of the RNA defect that causes this disease has been determined," lead author Matthew Disney said. "Based on these results, we designed compounds that, even in small amounts, significantly improve disease-associated defects in treated cells."
Myotonic dystrophy type 2 is a relatively rare form of muscular dystrophy that is somewhat milder than myotonic dystrophy type 1, the most common adult-onset form of the disease.
Both types of myotonic dystrophy are inherited disorders that involve progressive muscle wasting and weakness, and both are caused by a type of genetic defect known as a "RNA repeat expansion," a series of nucleotides repeated more times than normal in an individual's genetic code.
The repeat binds to the protein MBNL1, rendering it inactive and resulting in RNA splicing abnormalities-which lead to the disease.
Using information about the RNA's structure and movement, the scientists were able to design molecules to improve RNA function.
The new findings were confirmed using sophisticated computational models that show precisely how the small molecules interact with and alter the RNA structure over time.
Those predictive models matched what the scientists found in the study-that these new compounds bind to the repeat structure in a predictable and easily reproducible way, attacking the cause of the disease.
The study is published in journal ACS Chemical Biology.