EVIDENCE FOR AN ADDITIONAL ARCHAEBACTERIAL GENE-CLUSTER IN HALOBACTERIUM-MARISMORTUI ENCODING RIBOSOMAL-PROTEINS HL46E AND HL30

A small and extremely basic ribosomal protein (HL46e) has been purified from Halobacterium marismortui using reversed-phase high-performance liquid chromatography (HPLC). The amino acid sequence of the protein was determined by automated N-terminal and internal sequence analysis. Comparison of this sequence with other ribosomal protein sequences from eubacteria, archaebacteria and eukaryotes revealed a strong homology to SL46e from Sulfolobus solfataricus, YeaL46 from yeast and RL39 from rat. No significant sequence similarity was found to any eubacterial ribosomal protein so far known. Using a specific oligonucleotide probe the HL46e gene was identified, cloned and the nucleotide sequence including the 5′- and 3′-flanking regions were analysed. The HL46e gene is followed by the gene coding for HL30. A putative halobacterial promotor sequence with the motive 'TTTAAA' has been localized 32 bp upstream of the HL46e gene and a putative terminator sequence localized downstream from the HL30 gene. An equivalent to this HL46e/HL30 operon is apparently not present in Escherichia coli. © 1990.