Partial inhibition of polysomal ribosomes of Escherichia coli by streptomycin.

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Citation

Wallace BJ, Tai PC, Herzog EL, Davis BD

Partial inhibition of polysomal ribosomes of Escherichia coli by streptomycin.

Proc Natl Acad Sci U S A. 1973 Apr;70(4):1234-7. doi: 10.1073/pnas.70.4.1234.

PubMed ID
4577795 [ View in PubMed
]
Abstract

With purified initiation-free polysomes of E. coli, whether endogenous or formed in vitro on phage R17 RNA, streptomycin causes partial inhibition of chain elongation. The degree of inhibition is constant over a broad range of streptomycin concentration and decreases markedly with increasing Mg(++) concentration. Hence, streptomycin evidently complexes readily with polysomal ribosomes, causing a partial block in chain elongation. Streptomycin has already been shown to cause a complete block of chain elongation by free ribosomes forming initiation complexes in its presence. The production of a different effect on polysomal ribosomes explains how streptomycin can exert two mutually exclusive effects in cells: phenotypic suppression at low concentrations and irreversible inhibition of protein synthesis at higher concentrations. It also becomes possible to understand why killing by streptomycin is antagonized by agents (such as chloramphenicol) that cause a stable blockade of the ribosomes in polysomes.

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