A conserved rRNA switch is central to decoding site maturation on the small ribosomal subunit

Area of Science:

• Structural biology
• Molecular biology
• Microbiology

Background:

• Eukaryotic ribosome assembly mechanisms are increasingly understood.
• Bacterial ribosome assembly utilizes distinct factors lacking high-resolution structural data.

Purpose of the Study:

• To elucidate the structural mechanisms of bacterial ribosome assembly factors.
• To understand the late-stage folding of the 30S ribosomal subunit's decoding center.

Main Methods:

• Single-particle cryo-electron microscopy (cryo-EM).
• Visualization of bacterial ribosome assembly factors (RimP, RbfA, RsmA, RsgA).
• Analysis of eight structural snapshots of the 30S ribosomal subunit.

Main Results:

• Identified eight snapshots of late-stage 30S ribosomal subunit folding.
• Discovered a conserved secondary structure switch in 16S ribosomal RNA critical for decoding site maturation.
• Proposed a sequential action model for assembly factors coordinating this switch.

Conclusions:

• Bacterial and eukaryotic ribosome assembly share conserved folding principles.
• Assembly factors play crucial roles in controlling RNA structural transitions during ribosome biogenesis.
• High-resolution structures reveal conserved mechanisms in fundamental biological processes.