Structural heterogeneity of 30S and 50S ribosomal subunits in Bacillus licheniformis.

Proteins of free and polysome-derived ribosomal subunits of Bacillus licheniformis were fractionated by means of two-dimensional polyacrylamide gel electrophoresis. The free and derived 30S subunits have twelve protein components in common. Five proteins are present on the free 30S subunits only, whereas four proteins are exclusively found on the derived 30S subunits. The free and derived 50S subunits have at least twenty-eight proteins in common. Four proteins are unique for the derived and one for the free 50S subunits.