RESUMO
Streptomyces lividans (Sl) contains six ribosomal RNA (rRNA) gene sets, rrnA-F (Suzuki, Y., Ono, Y., Nagata, A. and Yamada, T. (1988) Molecular cloning and characterization of an rRNA operon in Streptomyces lividans TK21. J. Bacteriol. 170, 1631-1636). We have cloned the rrnB gene cluster. Physical mapping revealed that rrnB gene set is located on a 290 kb Asel fragment in the 11 to 12 o'clock region of the S. coelicolor A3(2) chromosome. The complete nucleotide (nt) sequence of Sl 23S rRNA has been determined. The structural gene of the Sl 23S rRNA codes for the 3108 nt RNA chain. The G+C content of the 23S rRNA is 57.3 mol%. The length of the spacer region between the 23S and 5S genes is 99 bp. Analysis of the sequences between the 16S and 23S genes and downstream of the 5S rRNA gene failed to identify any tRNA-like sequences. A secondary structure model of Sl 23 rRNA is proposed, based on the earlier published model of Gutell and Fox (Nucleic Acids Res. 16 (1988) 175-269).