Initiation of protein synthesis in vitro by a clostridial system. I. Specificity in the translation of natural messenger ribonucleic acids.

The homologous ribosomal systems from Escherichia co2i and Uostridium pasteurionum were compared for their ability to translate f2 RNA, formaldehyde-treated f2 RNA, T4 early messenger RNA, E. coli messenger RNA, and C. pasteurianum messenger RNA in protein synthesis assays in vitro. The E. co2i ribosomal system translated all five of these messengers, while the C. pasteurianum ribosomal system translated only the C. pusteurianum messenger RNA. The two ribosomal systems also had different characteristic magnesium profiles and exhibited different levels of endogenous activity in the protein synthesis assays. The messenger RNA responsible for the C. pasteurianum endogenous activity was shown to occur in the salt-washed ribosomes and not in the initiation factor fraction. The formaldehyde-treated f2 RNA and the C. pasteurianum messenger RNA exhibited different characteristics from the other types of messenger RNAs in their behavior with the E. coli ribosomal system in the protein synthesis assays. The two homologous ribosomal systems were also tested for their ability to bind [14C]formyl-Met-tRNA in response to different types of mRNA. The E. coli system bound fMettRNA in response to synthetic poly(A,G,U), f2 RNA, T4 early mRNA, and C. pasteurianum mRNA. The feurianum ribosomal system bound fMet-tRNA sponse to poly(A,G,U) and C. pasfeurianum mRNA f2 RNA or T4 early mRNA. C. pasin rebut not