Sequence of the gene for isoleucine tRNAj and the surrounding region in a ribosomai RNA operon of Escherichia coli

AA DNA fragment of about 2000 base pairs carrying the gene for has been cloned from a total Eco RI endonuclease digest of Escherichia coli DNA. Sequence analyses revealed that about the first 850 base pairs from one end of the fragment contain a nucleotide sequence corresponding to that in the 3'-end of 16S rRNA. The gene for tRNAIle follows the 16S rRNA gene and both genes flank a spacer sequence of 68 base pairs. The spacer region contains a repeating, a hair pin and a symmetrical structure when the sequence is viewed in the single stranded form. A notable hair pin struc-ture is also observed in the region adjacent to the 3'-end of the tRNA^ gene. In addition, about 850 base pairs from the other end of the DNA fragment have been found to contain the nucleotide sequence of the 5'-end of 23S rRNA. The presence of the genes for tRNAjle, 16S and 23S rRNA and the hybridization to tRNA*13 suggest that this cloned DNA is part of one of the E. coli rRNA operons carrying these two tRNA genes as a spacer