Studies on dissociation factor of bacterial ribosomes: Effect of antibiotics

García-Patrone, M.; Perazzolo, C.A.; Baralle, Francisco E.; González, Nélida S.; Algranati, Israel D.

doi:10.1016/0005-2787(71)90139-0

Cited by 15 publications

(1 citation statement)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In a recent study on the effect of several antibiotics, we observed that neomycin was also able to reassociate subunits (23); this associating capacity of the antibiotic was markedly enhanced in the presence of a heated ribosomal wash fraction from Bacillus stearothermophilus. The possibility arose that an association factor (AF) could be extracted, along with initiation and dissociation factors, from ribosomes of the thermophilic bacteria by salt solutions of high concentration.…”

mentioning

confidence: 99%

Association Factor of Ribosomal Subunits from Bacillus stearothermophilus

García-Patrone¹,

González²,

Algranati³

1971

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

View full text Add to dashboard Cite

The isolation of a new factor, which can cause the in vitro association of 30S and 50S ribosomal subunits at low Mg++ concentration, is described. The association factor is eluted together with the dissociation protein when ribosomes of Bacillus stearothermophilus are washed with salt solutions of high concentration. The association activity is heat-stable, whereas dissociation factor is inactivated after 10 min at 80'C. This treatment allows the separation of both factors. Several properties rule out the possibility that uncharged, aminoacyl-, or peptidyl-tRNA are responsible for the association process described in this report. Digestion with trypsin shows that the association factor contains at least two components, one of which is a protein.Bacterial ribosomes can be found as 70S particles, either free or complexed in monosomes and polysomes, and as 30S and 50S subunits (1). Several different conformations of each type of particle may also exist (2-8).Much evidence has accumulated to show that a cycle of ribosome dissociation and association of 30S and 50S subunits to 70S monosomes occurs during the successive rounds of protein synthesis (1, 9-12). The conditions that favor dissociation and association have been thoroughly studied. 70S ribosomes tend to dissociate with increasing temperature (13), in the presence of sulfhydryl reagents (14), or when the ratio of monovalent-to divalent-ion concentrations is high (15,16).A protein factor that causes the dissociation of 70S particles into 30S and 50S subunits has been recently obtained from different bacteria (17)(18)(19)(20). This factor (DF), necessary for cell survival, presumably dissociates ribosomes in vivo (12).Ribosomal subunits tend to reassociate at high Mg++ concentration (21), in the presence of polyamines (22), or when the subparticles are bound to peptidyl-tRNA or aminoacyl-tRNA (21).In a recent study on the effect of several antibiotics, we observed that neomycin was also able to reassociate subunits (23); this associating capacity of the antibiotic was markedly enhanced in the presence of a heated ribosomal wash fraction from Bacillus stearothermophilus. The possibility arose that an association factor (AF) could be extracted, along with initiation and dissociation factors, from ribosomes of the thermophilic bacteria by salt solutions of high concentration.In this report we will describe the isolation and some properties of a factor that can produce the in vitro association of ribosomal subunits to form a monomer at a relatively low Mg++ concentration, similar to the physiological level.Several attempts to detect the reversibility of ribosomal dissociation as mediated by DF have failed, except when the concentration of Mg++ was increased (1, 17). MATERIALS AND METHODS Escherichia coli Dio and B. stearothermophilus 1503-4Rwere grown as indicated (18).Trypsin (3-times crystallized) was purchased from Worthington; soybean trypsin-inhibitor (Worthington) was a generous gift from Dr. E. Cabib. RNase-free sucrose was obtained from Mann and tRN...

show abstract

mentioning

confidence: 99%