Sarah A. Woodson, Ph.D.

Title
Professor
Department
Department of Biophysics
Institution
Johns Hopkins University
Address
Jenkins Hall
3400 N. Charles Street
City, State, Zip
Baltimore, MD 21218-2864
Phone
(410) 516-2015
E-mail
swoodson[at]jhu.edu
Website
http://biophysics.jhu.edu/woodson/index.html
Research Field
Genetics
Award Year
1993

Research

The goal of our research is to understand how RNA folds into biologically active structures, and how the mechanisms of RNA folding determine the assembly of RNA-protein complexes. We are using group I introns or ribozymes from Tetrahymena thermophila (a unicellular ciliated protozoan) and Azoarcus sp. (a nitrogen fixing bacterium) to study the mechanisms of RNA folding. In collaboration with Michael Brenowitz and Mark Chance, we have developed a synchrotron “X-ray footprinting” method to probe the tertiary structure of RNA with millisecond time resolution. Using X-ray footprinting and other methods, we found that tertiary structure in the P4-P6 domain of the Tetrahymena ribozyme folds in 1-2 seconds, while the domain containing P3 and P7 folds very slowly (1-60 minutes). A variety of methods are needed to understand the folding mechanism of large RNAs. X-ray footprinting enables us to observe specific changes in the tertiary structure of the RNA on the millisecond time scale. Stopped-flow fluorescence spectroscopy monitors real-time changes in the global conformation of the RNA. Native polyacrylamide gel electrophoresis is a simple and direct way of separating intermediates.