Studies on the conversion of 60s yeast ribosomes into a 50S component.

The process of conversion of the larger (60s) subunit of yeast ribosomes into a 50s component was studied. The release of any RNA or protein material during conversion was assayed by using (32)P- or (35)S-labelled ribosomes; ribosomal RNA distributions of the particles were examined and protein/RNA ratios of subunits were determined. The change in sedimentation coefficients was found to be due, not to loss of material, but to a structural change. The change in structure was shown by electron microscopy.