RESUMO
A concentration of 10 mug of fluorophenylalanine per ml added to a chemically defined medium reduced by 100-fold the number of bacteriophage MS2 produced on Escherichia coli C3000 and increased the latent period. Fluorophenylalanine was most effective when added concurrent with infection. Addition of a 10-fold greater concentration of phenylalanine reversed the inhibition caused by fluorophenylalanine. Radioactive fluorophenylalanine was incorporated into the coat protein. The four phenylalanine-containing chymotryptic peptides are not equally accessible to fluorophenylalanine. Only two of the peptides are highly labeled by fluorophenylalanine. Incorporation of fluorophenylalanine decreased the specific infectivity and the rate of adsorption but did not increase the sensitivity of the whole virus to ribonuclease. MS2 ribonucleic acid (RNA) functioned as messenger RNA for the incorporation of both phenylalanine and fluorophenylalanine in a cell-free incorporating system from E. coli.
