Inhibition of 'in vitro' Protein Synthesis by 'Shigella dysenteriae' 1 Toxin.

摘要

A toxin produced by S. dysenteriae 1 has been purified to near homogeneity. Preliminary investigation of its possible effect on in vitro mammalian protein synthesis shows that it has no effect on amino-acylation of tRNA. However, the transfer of amino acids from AA-tRNA to ribosomes or polysomes to effect the polypeptide chain synthesis is inhibited in the presence of microgram quantities of toxin. This is evidenced by inhibition of poly U directed polyphenylalanine synthesis using washed ribosomes as well as the synthesis of nascent polypeptide chains using polysomes and mixtures of amino acids. Unlike Diphtheria toxin NAD+ is not required by S. dysenteriae 1 toxin for its activity in this reaction. (Author)