Mechanism of protection of protein synthesis against streptomycin inhibition in a producing strain.

The influence of streptomycin (SM) on protein synthesis in a SM-producing strain was investigated using polyuridylic acid-directed polyphenylalanine synthesis in cell-free extracts. Tolerance of protein synthesis to SM developed with increasing culture age of cells and could be attributed to a decrease in affinity of the ribosomes for SM and in increase in SM 6-kinase activity in cells. SM 6-phosphate produced from SM by SM 6-kinase did not bind to ribosomes and, furthermore, ribosome-bound SM was effectively released on phosphorylation with SM 6-kinase. Also a decrease in cell permeability to SM during the production phase may contribute in protecting protein synthesis from the antibiotic.