University of Arizona BIO5 researchers feel the spring in RNA

[Source: Deborah Dawn, Bio5 Institute] -- Researchers from the BIO5 Institute at The University of Arizona have used optical tweezers technology to observe the unraveling of molecular sized helices within individual molecules of messenger RNA. This important class of RNA molecules is the essential connection between the genomic information of the DNA double helix, and the complex 3D structure of the proteins that perform the essential functions of life. This work was performed in the lab of BIO5 member Koen Visscher, PhD, who also holds joint appointments in the departments of physics and molecular and cellular biology.

Using an “optical tweezers,” a device employing laser beams to catch and hold particles only millionths of a meter across, former physics graduate student Yeonee Seol, with assistance from BIO5's Quantitative Biology Consortium postdoctoral research associate Gary Skinner, PhD, applied tiny forces to individual molecules of RNA. The molecules in question, repeated chains of the RNA base “A” or “C,” turned out to adopt a helical shape, and as these molecules were pulled progressively harder and harder, this helix would gradually unwind.

The experimental data was modeled in collaboration with Arnaud Buhot, PhD, and Avraham Halperin, PhD, of the Commissariat a l'Energie Atomique in Grenoble, France, who successfully developed a mathematical model that accurately predicts how the length of these helical molecules should change as increasing force is applied. From this model, fundamental mechanical and elastic properties of RNA can be accurately measured.

Researchers hope that such quantitative, physical information will assist in the further understanding of the molecular, and mechanical, underpinnings of life. This research appears in the April 13, 2007 issue of Physical Review Letters.