[Topography of rRNA in ribosomes. Effect of pancreatic RNAse on small ribosomal subunits].

The treatment of E. coli 30S ribosome subunits with pancreatic RNase under certain conditions resulted in the release of rRNA (about 15%). The subunit retained as a whole structure: sedimentation coefficient was unchanged and no protein release was observed. The released RNA is a set of oligonucleotides from 1 to 9 bases, except hepta- and octanenucleotides. Base composition of this RNA fraction is similar to 16S RNA, a slight increase of purines content being due to the specificity of nuclease. Analysis of isoplit content has revealed that a spliting of long oligonucleotides in stechiometric amount from 30S subunits takes place: one nonanucleotide, one hexanucleotide and two pentanucleotides.