Complete nucleotide sequence of the single ribosomal RNA operon of Halobacterium halobium: secondary structure of the archaebacterial 23S rRNA

Abstract

The complete nucleotide sequence of the rRNA operon of an archaebacterium Halobacterium halobium is presented. The structural genes are arranged in the order 16S-23S-5S and are tightly physically linked, the intergenic spacers being 528 and 110 bp long, respectively. The 16S-23S spacer codes for the alanine tRNA gene. Putative transcription initiation and termination signals and transcript processing signals contained in the noncoding regions are discussed. Proceeding from the nucleotide sequence of the 23S rRNA gene, the secondary structure of the archaebacterial 23S rRNA is proposed. The secondary structure models of the 23S-like rRNA of eubacteria, archaebacteria and eukaryotes are compared and the common evolutionary conserved core of this molecule is identified.