Organization of three rRNA (rrn) operons from Sphingobium chungbukense DJ77.

The nucleotide sequences of all three rRNA operons (rrnA, rrnB, and rrnC) of Sphingobium chungbukense DJ77 were determined. The three rrn operons have the same gene order (16S rRNA-tRNAIle-tRNAAla-23S rRNA-5S rRNA-tRNAfMet). The nucleotide sequences were identical over a 5,468 bp region spanning the 16S rRNA gene to the 5S rRNA gene. Variability was observed in the 5S rRNA-tRNAfMet spacer sequence of rrnB. The tRNAfMet gene sequences were identical except for two bases (T5794 and A5871 in rrnB, T5942 and A5956 in rrnA, but C5942 and G5956 in rrnC). Comparative sequence analyses of ribosomal RNA operons from DJ77 with those of the class Alphaproteobacteria, to which the genus Sphingobium belongs, reveal close evolutionary relationships with other members of the order Sphingomonadales.