Showing papers by "Bernard D. Davis published in 1973"
TL;DR: Even though the ribosome normally initiates via subunits, it is released from RNA by a conformational change in the intact 70 S particle, rather than by dissociation.
44 citations
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TL;DR: It is found that after streptomycin has virtually halted protein synthesis in cells of Escherichia coli K12 a substantial (though reduced) level of polysomes persists, suggesting that in sensitive cells damage to only a fraction of the ribosomal population by strePTomycin may be sufficient to block protein synthesis.
37 citations
TL;DR: Str-inhibited dissociation may be the limiting step in this reinitiation, for the polysome level is much lower in Str-treated cells of strain W than in those of K12, and Str impairs dissociation much more with ribosomes of the former strain.
16 citations
TL;DR: 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, and 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.
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.
13 citations
TL;DR: Findings indicate that I in codon position 2 can pair readily not only with C but also with A (complementing valine codon GU_), and suggest that the rotation model for I·A pairing merits further exploration.
10 citations