Approaching translation at atomic resolution

Area of Science:

• Molecular biology
• Structural biology
• Biochemistry

Background:

• Decades of biochemical research have elucidated fundamental aspects of protein synthesis.
• The ribosome, a complex molecular machine, is central to translation.
• Understanding the ribosome's structure is key to deciphering its function.

Purpose of the Study:

• To determine the atomic resolution structures of the 50S and 30S ribosomal subunits.
• To provide molecular insights into the mechanisms of translation and ribosomal fidelity.
• To identify the RNA-based active site for peptide bond formation.

Main Methods:

• X-ray diffraction was employed to solve the atomic resolution structures of ribosomal particles.
• Analysis of the obtained structures focused on RNA and protein folds.
• Localization of tRNA binding sites and the peptide bond formation active site.

Main Results:

• Atomic resolution structures of 50S and 30S ribosomal subunits were determined.
• Unusual folds of ribosomal RNAs and proteins were observed.
• The active site for peptide bond formation was localized to RNA, identifying the ribosome as a ribozyme.
• tRNA binding sites were located, and mechanisms for ribosomal fidelity were proposed.
• The 30S subunit's three-domain structure suggests domain movements for translocation.

Conclusions:

• The ribosome functions as a ribozyme, with RNA catalyzing peptide bond formation.
• The determined structures provide molecular explanations for translation fidelity and translocation.
• These findings usher in a new molecular era for ribosome research, integrating structural and biochemical data.