Nature of guanine oxidation in RNA produced via the flash-quench technique and direct oxidation with metal-oxo complexes

BIOL 228

Dana R. Holcomb, holcombd@email.unc.edu1, Patricia A. Ropp1, Elizabeth C. Theil, etheil@chori.org2, and Holden Thorp, holden@unc.edu1. (1) Department of Chemistry, University of North Carolina at Chapel Hill, Campus Box 3290, Caudill and Kenan Laboratories, Chapel Hill, NC 27599-3290, (2) CHORI (Children's Hopsital Oakland Research Institute), Center for BioIron at CHORI (Children's Hospital Oakland Research Institute), 5700 Martin Luther King, Jr. Way, Oakland, CA 94609
Oxidation of RNA can be effected by two different assays: a photochemical, electron-transfer method, termed “flash-quench” and direct oxidation by metal-oxo complexes. The flash-quench method produces selective oxidation at guanine using a metal photosensitizer, Ru(bpy)33+ (bpy = 2,2′–bipyridine), and quencher, Co(NH3)5Cl2+. We have optimized the flash-quench technique for the following RNAs: tRNA, iron-responsive element (IRE), and two mutant IREs. The other method is a chemical footprinting technique involving an oxoruthenium (IV) complex (RuO2+) that oxidizes guanines. Comparison of the two methods shows that the flash-quench technique provides a static snapshot of the guanine accessibility while the RuO2+ complex selectively oxidizes flexible guanines that can undergo chemical reaction.
 

Frontiers in Chemical Biology
5:00 PM-7:00 PM, Wednesday, August 22, 2007 BCEC -- Exhibit Hall - B2, Poster

Division of Biological Chemistry

The 234th ACS National Meeting, Boston, MA, August 19-23, 2007