NUCLEOTIDE-SEQUENCE ANALYSIS OF THE 23S RIBOSOMAL-RNA-ENCODING GENE OF BARTONELLA-BACILLIFORMIS

We report the cloning and characterization of the 23S ribosomal RNA (r RNA)-encoding gene (rDNA) of Bartonella bacilliformis (Bb). The 2821-b p gene is preceded by an 11-nucleotide (nt) inverted repeat (IR) locat ed 81 nt upstream in the tRNAA(Ala)-23S rDNA intergenic spacer. The ge ne is followed by an 8-nt IR, five nt downstream in the 23S-5S rDNA in tergenic spacer. The nt sequence of the Bb 23S rDNA is most similar to the 23S rDNA of Rhodopseudomonas palustris (Rp), with 85.4% sequence identity. The Bb 23S rDNA has 77.8% identity to the same gene from Esc herichia coli (Ec). Secondary structure predictions indicate that the large subunit (LSU) Bb rRNA contains two smaller stem-loops at nt 1459 -1544 and 1658-1685, as compared to the corresponding loops from Ec (n t 1405-1597 and 1707-1751, respectively). In addition, the Bb 23S rRNA has a large 72-nt stem-loop at nt 130-201, as compared to the Ec 18-n t stem-loop (nt 131-148). There is no Bb homologue of the 15-nt stem-l oop at the 3' end of the Ec molecule (nt 2791-2805). The Bb 23S rRNA l acks the large stem-loop present in the LSU rRNA of closely related Rh odobacter sphaeroides (Rs) (nt position 1225-1331) which is thought to be involved in cleavage of 23S RNA precursor molecules into 16S and 1 4S rRNA species. This is the first LSU rDNA nt sequence for any member of the Bartonellaceae family.