| Abstract: | Staring from low molecular weight RNA obtained from rainbow trout (Salmo gairdnerii) liver, 5S ribosomal RNA (rRNA) was highly purified by successive chromatography on columns of DEAE-Sephadex A50 and Sephadex G100. Products of complete and partial digestions on this RNA with pancreatic ribonuclease (RNase A) EC 3.1.4.22] and RNase T EC 3.1.4.8] were isolated and sequenced by conventional and high-performance liquid chromatography (HPLC) procedures. The nucleotide sequence of this RNA thus established was compared with those of five other vertebrae 5S rRNAs, and the rates of base substitution per site per year were found to be nearly constant in these RNAs. The analyses of the partial digests of the trout 5S rRNA revealed several sites susceptible to RNase attack, which could be accounted for by the secondary structure model for eukaryotic 5S rRNAs proposed by Nishikawa and Takemura (1). |
