Cleavage of 23-S RNA in 50-S ribosomes into a 5′-terminal and a 3′-terminal fragment by pancreatic ribonuclease

Abstract

Pancreatic ribonuclease cleaves the 23-S RNA in the 50-S ribosomal subunit into two unequal fragments, the larger one comes from the 3′-end and the smaller one from the 5′-end. Similar degradation of the 23-S RNA is also observed after prolonged storage of 50-S subunits. In either case the 5′-termini of the larger fragment generated contain predominantly adenine residues, suggesting that cleavage may be very specific. Although the smaller fragment comes from the 5′-end of the 23-S RNA, under certain conditions it undergoes further partial degradation of its 5′-terminal portion. These results are consistent with a unique secondary and tertiary structure for the 23-S RNA in the 50-S ribosomal subunit.