Photoinduced cleavage by a rhodium complex at G center dot U mismatches and exposed guanines in large and small RNAs

Abstract

Photoinduced cleavage reactions by the rhodium complex tris(4,7-diphenyl-1,10-phenanthroline)rhodium(III) {Rh(DIP)(3)(3+)} with three RNA hairpins, r(GGGGU UCGCUC CACCA) (16,nucleotide, tetraloop(Al2)), r(GGGGCUAUAGCUCUAGCUC CACCA) (24 nucleotide, microhelix(Ala)), and r(GGCGGUUAGAUAUCGCC) (17 nucleotide, 790 loop), and full-length (1542 nucleotide) 16S rRNA from Escherichia coli were investigated. The cleavage reactions were monitored by gel electrophoresis and the sites of cleavage by Rh(DIP)(3)(3+) were determined by comparisons with chemical or enzymatic sequencing reactions. In general, RNA backbone scission by the metal complex was induced at G-U mismatches and at exposed G residues. The cleavage activity was observed on the three small RNA hairpins as well as on the isolated 1542-nucleotide ribosomal RNA. (C) 2002 Societe francaise de biochimie et biologie moleculaire/Editions scientifiques et medicales Elsevier SAS. All rights reserved.