Formylmethionyl-tRNA Dependence of Amino Acid Incorporation in Extracts of Trimethoprim-Treated Escherichia coli

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Science  28 Oct 1966:
Vol. 154, Issue 3748, pp. 524-527
DOI: 10.1126/science.154.3748.524


The growth of Escherichia coli cells in rich, thymine-containing medium was stopped by the addition of trimethoprim, an inhibitor of dihydrofolate reductase. In an extract of these cells (supernatant from an extract centrifuged at 30,000g) amino acid incorporation at 0.005M magnesium-ion concentration, directed by f2 bacteriophage RNA depended strictly on added formylmethionyl-transfer RNA or N5-formyltetrahydrofolate. Hydroxylamine inhibited the amino acid incorporation directed by f2 bacteriophage RNA, when N5-formyltetrahydrofolate had been added, but had no effect when formylmethionyl transfer RNA had been added.