Specific alteration of the 30S ribosomal subunits of Bacillus subtilis during sporulation

Active 30S ribosomal subunits were isolated from vegetative and sporulating cells of Bacillus subtilis. Both subunits were able to function in polyuridylic acid of phage phie messenger ribonucleic acid-dependent protein synthesis in vitro. The sporulation 30S subunits were highly active in polyuridylic acid-dependent polyphenylalanine synthesis but showed a reduced activity in the presence of natural messenger ribonucleic acid as compared with their vegetative counter-parts. The reduced activity was independent of the source of 50S particles and initiation factors (vegetative or sporulation). The alteration of the 30S sporulation subunits appears to be related to the sporulation process, since the same subunits isolated from stationary-phase cells of an asporogenic mutant did not show any impairment in protein synthesis in vitro.