Effect of polyamines on the binding of dihydrostreptomycin and N-acetylphenylalanyl-tRNA to ribosomes from Escherichia coli.

Abstract

1 The bindings of dihydrostreptomycin and N-acetylphenylalanyl-tRNA to Escherichia coli (Q13) ribosomes, which are dependent upon the concentration of Mg2+, were enhanced by spermine, spermidine or putrescine at low concentrations of Mg2+. However, critical levels of Mg2+ which are specific for each polyamine were essential for the enhancement. 2 When the amount of ribosomes was increased, increasing concentration of spermine was required for the same level of stimulation. 3 The binding of spermine to the ribosomes proceeded rapidly and the amount of spermine bound was independent of the incubation temperature from 0°C to 37°C. The stimulation of dihydrostreptomycin binding ability of ribosomes by spermine, however, was dependent upon the temperature and the period of the incubation. 4 When ribosomes were preincubated at 37°C with spermine and adsorbed on a Millipore filter, the spermine · ribosome complex on the filter could efficiently bind dihydrostreptomycin. Although washing with an ice-cold buffer solution containing a high concentration of NH4Cl removed most of the bound spermine from the spermine · ribosome complex, the ribosomes remained active in binding dihydrostreptomycin.