Specific cleavage of ribosomal RNA caused by alpha sarcin

Alpha sarcin causes the specific cleavage of RNA from 80S ribosomes and 60S subunits of yeast, but not from the 40S subunits to produce a small rna fragment. The fragment was also produced on treatment of the 60S subunits of vheat germ ribosomes. The fragment has a molecular weight of 100,000 and is a cleavage product of the large RNA species in the 60S subunits. The fragment is not derived from the 5′end of the yeast 25S RNA nor does it bind to 5.8S RNA and we propose that the fragment represents the 3′ terminal 320 nucleotides of 25S rRNA. The ability to produce fragment could not be separated from the ability of alpha sarcin to inhibit protein synthesis. Alpha sarcin also causes the specific cleavage of the 23S RNA of the IS. coli subunit to produce a smaller fragment of RNA than that produced from eukaryote ribosomes.