Polypeptide Synthesis by Extracts from Escherichia coli Treated with T2 Ghosts

Abstract

Infection of Escherichia coli B in inorganic salts-glycerol with a multiplicity of deoxyribonucleic acid-less T2 “ghosts” just sufficient to block all protein synthesis results in both viable and killed bacteria. We enriched for the viable cells by a combination of lysozyme treatment and filtration and measured the in vitro capacity of their extracts to synthesize polypeptides. Without added template ribonucleic acid (RNA), such “ghost extracts” incorporate amino acids (endogenous synthesis) at approximately one-half the rate as do extracts from uninfected bacteria. However, they are unable to use added synthetic or natural template RNAs for peptide synthesis. Some activity can be observed but only at high concentrations of Mg 2+ . These results suggest that ghost infection may result in a blockage of ribosomes during translation. Mixing experiments show that the incapacity of ghost extracts to translate added template RNA is due to a defect in the ribosomes.