Digests double-stranded RNA. Involved in the processing of ribosomal RNA transcript to yield the immediate precursors to the large and small rRNAs (23S and 16S). Removes small helical intervening sequences (IVSs) from all 7 of the 23S rRNA transcripts. Probably also processes some mRNAs, and tRNAs when they are encoded in the rRNA operon. Probably processes pre-crRNA and tracrRNA of type II CRISPR loci if present in the organism. Endonucleolytic cleavage to 5'-phosphomonoester. Homodimer. Accumulation of full-length 23S rRNA as well as larger precursor rRNA transcripts. Strain grows slower than wild-type. This organism contains small helical (90-110 nucleotide) intervening sequences (IVSs) in all 7 23S rRNA genes at either the 550-bp or 1170-bp positions or both, accumulating the 23S rRNA as 2.4, 1.7, 1.6, 0.7, and 0.5 kb pieces. Belongs to the ribonuclease III family.