RNase catalyzed hydrolysis of ribosomes in several functional states

The RNase A catalyzed hydrolysis of rRNA in ribosomes has been studied for nonwashed 50S and 70S ribosomes, for washed 50S and 70S ribosomes, for runoff 50S ribosomes and for 70S ribosomes in polysomes. The regions available to hydrolysis in the 50S ribosome remain available when the 50S ribosomes become a part of a 70S ribosome or a polysome. The regions available to hydrolysis in the 30S ribosome become unavailable when the 30S ribosome becomes part of a 70S ribosome or a polysome. Removal of tRNA, mRNA and factors from the 50S and 70S ribosome lowers the rate of hydrolysis of one site in the 23S rRNA. This shows that the conformation of one region of the 23S RNA changes for ribosomes in different functional states.