Conformational switch in the decoding region of 16S rRNA during aminoacyl-tRNA selection on the ribosome

Area of Science:

• Molecular Biology
• Biochemistry
• Antibiotic Resistance

Background:

• Aminoglycoside antibiotics are crucial for treating bacterial infections.
• These antibiotics target the bacterial ribosome, specifically the 16S ribosomal RNA (rRNA).
• The precise mechanism by which aminoglycosides induce translational errors is still under investigation.

Purpose of the Study:

• To elucidate the structural and kinetic mechanisms by which aminoglycoside antibiotics affect 16S rRNA and protein synthesis fidelity.
• To understand how aminoglycoside binding influences codon recognition and ribosomal rearrangements.
• To identify the conformational transitions in 16S rRNA critical for decoding accuracy.

Main Methods:

• Kinetic analysis of ribosomal function.
• Structural studies of 16S rRNA in the presence of aminoglycosides.
• Measurement of amino acid incorporation rates and fidelity.

Main Results:

• Aminoglycoside binding induces a specific structure in the 16S rRNA decoding center.
• Antibiotic binding stabilizes the recognition complex with near-cognate amino acids, increasing misincorporation.
• Two rate-limiting rearrangement steps in amino acid incorporation are accelerated by aminoglycosides, affecting both cognate and near-cognate recognition.

Conclusions:

• Aminoglycoside-induced structural changes in 16S rRNA are key to their mechanism of action.
• These antibiotics promote a transition of 16S rRNA to a conformation that enhances decoding fidelity.
• Understanding these mechanisms can inform the development of new antibiotics and strategies to combat resistance.