Nucleotide sequence of the 23S rRNA from Haloferax mediterranei and phylogenetic analysis of halophilic archaea based on LSU rRNA

23S rRNA gene from the halophilic archaeon Haloferax mediterraneai (strain ATCC 33500) was cloned and sequenced. Proceeding from the 2,912 nucleotides long sequence, the secondary structure of Haloferax genus large subunit rRNA was proposed. Haloferax mediterranei intergenic spacers 16S/23S and 23S/5S were also sequenced, and found to be 382 and 116 nucleotides long respectively. The 16S/23S spacer showed an Ala-tRNA intervening sequence, which is a common feature in Euryarchaeota. Sequence analysis of 23S rRNA and 16S rRNA was performed for the six organisms from thc family Halobacteriaceae with both available gene sequences. Phylogenetic trees with completely different topology were obtained using both molecules.