Translation error clusters induced by aminoglycoside antibiotics

Area of Science:

• Microbiology
• Molecular Biology
• Biochemistry

Background:

• Aminoglycoside antibiotics are crucial for treating bacterial infections.
• These drugs function by targeting bacterial ribosomes and inducing errors during protein synthesis (mistranslation).
• The precise mechanisms by which these translation errors lead to bacterial cell death remain incompletely understood.

Purpose of the Study:

• To investigate the nature and impact of translation errors induced by aminoglycoside antibiotics in vivo.
• To determine if specific types of errors, such as clustered substitutions, are responsible for the bactericidal effects.
• To elucidate the relationship between aminoglycoside properties, error patterns, and bacterial cell death.

Main Methods:

• Quantitative mass spectrometry was employed to analyze the proteome of bacteria exposed to aminoglycosides.
• The study focused on identifying and characterizing amino acid substitutions within full-length proteins.
• Analysis included assessing the frequency, length, and composition of error clusters and their correlation with drug concentration and properties.

Main Results:

• Bactericidal aminoglycosides induce not only single amino acid substitutions but also clusters of errors within proteins.
• These error clusters can involve up to four consecutive amino acid substitutions.
• Downstream errors within a cluster occurred at significantly higher frequencies (up to 10,000-fold) than the initial error and were independent of intracellular drug concentration.
• The formation and characteristics of error clusters are influenced by both the aminoglycoside's misreading propensity and its ability to inhibit ribosome translocation.

Conclusions:

• Error clusters represent a distinct and significant class of aminoglycoside-induced mistranslation events in vivo.
• These clustered errors are likely the primary drivers of proteotoxic stress at low aminoglycoside concentrations.
• The formation of error clusters may play a critical role in the autocatalytic uptake of aminoglycosides, enhancing their bactericidal activity.