Use of the cytotoxic nuclease alpha-sarcin to identify the binding site on eukaryotic 5 S ribosomal ribonucleic acid for the ribosomal protein L5.

Treatment of the large subunit of eukaryotic ribosomes with EDTA releases a 7 S ribonucleoprotein complex that contains protein L5 and 5 S rRNA. The region of rat 5 S rRNA that is protected by protein L5 from digestion with the ribonuclease alpha-sarcin includes nucleotides 1-10, 12-22, and 64-116. This domain approximates the combined binding sites for the three proteins (L5, L18, and L25) that associate with Escherichia coli 5 S rRNA. In addition, the region of 5 S rRNA protected by rat ribosomal protein L5 corresponds closely to that occupied by Xenopus transcription factor IIIA.