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Conformational changes in the ribosome induced by translational miscoding agents
1Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0314, USA.
Abstract:
Ribosomes are dynamic complexes responsible for translating the genetic information encoded in mRNAs to proteins. The accuracy of this process is vital to the survival of an organism, and is often compromised by translational miscoding agents. Aminoglycosides are a group of miscoding agents that bind to the ribosome and reduce the fidelity of translation. Previous studies have shown that aminoglycosides alter the higher order structure of the ribosome. Here, we used a toeprinting assay to how that streptomycin, neomycin, kanamycin, gentamycin, and hygromycin B trigger conformational changes within Escherichia coli ribosome. Miscoding agents viomycin and 30% ethanol also cause similar structural changes within the ribosome. In contrast, antibiotics that do not cause miscoding, such as tetracycline, chloramphenicol, erythromycin, fusidic acid and spectinomycin, do not induce the conformational changes triggered by miscoding agents. Furthermore, ribosomes isolated from strains that are either streptomycin resistant or dependent for growth do not show these conformational changes in the presence of streptomycin. These results correlate structural changes in the ribosome induced by miscoding agents in vitro with their in vivo phenotype.
Insights
Translational miscoding agents like aminoglycosides alter ribosome structure, impacting protein synthesis accuracy. This study confirms these structural changes correlate with their effects in living organisms.
Area of Science:
- Molecular Biology
- Genetics
- Biochemistry
Background:
- Ribosomes translate mRNA to proteins, a crucial process for life.
- Translational fidelity is vital; miscoding agents compromise this accuracy.
- Aminoglycosides are miscoding agents known to affect ribosome structure and translation.
Purpose of the Study:
- To investigate how miscoding agents induce conformational changes in Escherichia coli ribosomes.
- To correlate in vitro observed structural changes with in vivo phenotypes.
Main Methods:
- Utilized a toeprinting assay to detect structural alterations in ribosomes.
- Tested various aminoglycosides (streptomycin, neomycin, kanamycin, gentamycin, hygromycin B), miscoding agents (viomycin, ethanol), and non-miscoding antibiotics (tetracycline, chloramphenicol, erythromycin, fusidic acid, spectinomycin).
- Examined ribosomes from streptomycin-resistant and streptomycin-dependent strains.
Main Results:
- Streptomycin, neomycin, kanamycin, gentamycin, and hygromycin B induced conformational changes in E. coli ribosomes.
- Other miscoding agents (viomycin, ethanol) also caused similar structural changes.
- Non-miscoding antibiotics did not induce these conformational changes.
- Ribosomes from streptomycin-resistant or dependent strains did not exhibit changes with streptomycin.
Conclusions:
- Miscoding agents trigger specific conformational changes in bacterial ribosomes.
- These structural alterations are linked to the observed in vivo effects of miscoding agents.
- The findings provide a molecular basis for understanding aminoglycoside action.