The dependence of cell-free protein synthesis in E. coli upon naturally occurring or synthetic polyribonucleotides

A stable cell-free system has been obtained from E. coli which incorporates C14-valine into protein at a rapid rate. It was shown that this apparent protein synthesis was energy-dependent, was stimulated by a mixture of L-amino acids, and was markedly inhibited by RNAase, puromycin, and chloramphenicol.1 The present communication describes a novel characteristic of the system, that is, a requirement for template RNA, needed for amino acid incorporation even in the presence of soluble RNA and ribosomes. It will also be shown that the amino acid incorporation stimulated by the addition of template RNA has many properties expected of de novo protein synthesis. Naturally occurring RNA as well as a synthetic polynucleotide were active in this system. The synthetic polynucleotide appears to contain the code for the synthesis of a “protein” containing only one amino acid. Part of these data have been presented in preliminary reports.2, 3