Reutilization of ribosomal protein in vivo for the formation of new ribosomal particles in Escherichia coli B

Abstract 1. 1. When starved for Mg 2+ , E. coli B cells almost completely lose the ribosomes. The 105 000 × g supernatant of an extract from Mg 2+ -starved cells contains many more basic proteins than that from unstarved cells. 2. 2. Mg 2+ -starved cells, after readdition of Mg 2+ , are able to synthesize complete ribosomal particles, even in the presence of chloramphenicol. Proteins contained in these particles were synthesized before chloramphenicol was added to the culture. 3. 3. Ribosomal particles synthesized during recovery from Mg 2+ starvation in the presence of chloramphenicol contain newly synthesized ribosomal RNA. 4. 4. The possibility of a coordination between ribosomal protein synthesis and ribosomal RNA synthesis is entertained.