Poster abstracts

Poster number 55 submitted by Caroline Vizthum

The Adduct between RluA and 5-Fluorouridine in RNA: Is it Covalent (or Just Really Tight)?

Caroline A. Vizthum (Department of Chemistry and Biochemistry, University of Delaware), Charmaine Hoang (Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA), Adrian R. Ferré-D'Amaré (Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA), Eugene G. Mueller (Department of Chemistry and Biochemistry, University of Delaware)

Abstract:
Of the nearly 100 known post-translational modifications of RNA, the most common is the conversion of uridine (U) to pseudouridine (Ψ). The enzymes responsible for this conversion, the Ψ synthases, are a superfamily of enzymes that share no global sequence similarity yet share the same core β-sheet fold. Crystal structures of representative members of each family have been solved, most recently RluA in complex with a stem-loop RNA (Hoang, C., et al., and Ferré-D'Amaré, Mol Cell, in press). Biochemical studies have shown that RluA is potently inhibited by RNA containing 5-fluorouridine, and RluA and the inhibitory RNA co-migrate on both SDS-PAGE and urea-PAGE gels, suggesting a covalent protein-RNA adduct. However, no such covalent bond is observed in the cocrystal structure. A variety of spectroscopic and biochemical techniques have been employed to probe for a covalent linkage between RluA and 5-fluorouridine in RNA, and the results are presented here.

Keywords: pseudouridine synthase, RluA