Selective messenger translation by Bacillus subtilis ribosomes.

The in vitro B. subtilis protein synthesizing system is very restricted in its ability to translate E. coli phage messenger RNA's, specifically phage T4 RNA, even though it actively translates its proper mRNA species. In contrast, the E. coli system translates with similar efficiency mRNA from either source. The initiation factors from the two systems are functionally interchangeable. The 30S B. subtilis ribosomal subunit is responsible for the limited template specificity of the B. subtilis ribosomes. Although the efficiency of the T4RNA directed F Met-tRNA binding by B. subtilis ribosomes is less than that of SPOI RNA-directed binding, the most restrictive step in the translation of T4RNA by B. subtilis ribosomes appears to be at the level of the formation of the first peptide bond, as measured by F Metpuromycin formation.