C-SBP2 forms highly stable complexes with RNAs containing an extended internal loop

Abstract

<p><b>Copyright information:</b></p><p>Taken from "An improved definition of the RNA-binding specificity of SECIS-binding protein 2, an essential component of the selenocysteine incorporation machinery"</p><p></p><p>Nucleic Acids Research 2007;35(6):1868-1884.</p><p>Published online 1 Mar 2007</p><p>PMCID:PMC1874613.</p><p>© 2007 The Author(s)</p> The stabilities of the complexes formed between C-SBP2 and Snu13p and the Se1:Ins + loop () and SelN () RNAs were tested by competition experiments. RNA–protein complexes were formed by using 5 fmol of 5′-end labeled Se1:Ins + loop or SelN RNAs and C-SBP2 (300 nM) or Snu13p (1000 or 300 nM). The RNA–protein complexes were challenged with increasing concentrations of cold Se1:Ins + loop or SelN RNAs (10–100 000- and 10–40 000-fold molar excess, respectively, as indicated below the lanes). The remaining complexes were fractionated by gel electrophoresis. () Comparison of the relative stabilities of the Snu13p–SelN and C-SBP2–SelN complexes. RNP complexes formed with C-SBP2 at 300 nM were challenged by addition of an excess of Snu13p protein and vice versa. Complexes formed with Snu13p at 300 nM were challenged by addition of an excess of C-SBP2. The remaining complexes were fractionated by gel electrophoresis. The identities and concentrations of the protein competitors used in the assays are indicated below the lanes