Genetic studies of the ribosomal proteins in Escherichia coli. XI. Mapping of the genes for L21, L27, S15 and S21 by using hybrid bacteria and over-production of these proteins in the merodiploid strains.

E. coli episomes which cover argG region were transferred to S. marcescens and ribosomal proteins (r-proteins) from these hybrid strains were analyzed by two-dimensional (2D) polyacrylamide gel electrophoresis. Three E. coli r-proteins L21, L27 and S15 could be detected in the ribosomes from the hybrid strains. The relative rate of synthesis of the individual r-proteins were determined for E. coli merodiploid strains harboring these episomes. Over-production of three r-proteins L21, L27 and S21 (but not S15) was observed in the merodiploid strains.