Structure of RNA in ribosomes

Area of Science:

• Molecular Biology
• Biochemistry
• Structural Biology

Background:

• Ribosomes are essential molecular machines composed of ribosomal RNA (rRNA) and proteins.
• Understanding the structural organization and interactions within ribosomes is crucial for deciphering protein synthesis.
• Ribosomal proteins play a role in stabilizing rRNA structure and facilitating ribosome function.

Purpose of the Study:

• To investigate the susceptibility of 23S and 16S ribosomal RNA to hydrolysis by ribonuclease A.
• To determine the impact of ribosomal proteins on RNA conformation and accessibility.
• To identify regions of rRNA protected from enzymatic degradation within the 50S and 30S ribosomal subunits.

Main Methods:

• Hydrolysis of 50S and 30S ribosomal subunits and isolated 23S and 16S rRNA using ribonuclease A.
• Quantification of reaction rate constants and the number of RNA fragments produced.
• Analysis of conformational changes in 23S RNA upon extraction from the ribosome.

Main Results:

• Ribonuclease A hydrolysis generated distinct sets of fragments for both ribosomal subunits and isolated RNAs.
• The rate constants for hydrolysis varied between the different RNA preparations.
• 23S RNA exhibited altered conformation when dissociated from ribosomal proteins.
• Specific segments of 23S and 16S rRNA within the 50S and 30S ribosomes were resistant to ribonuclease A digestion, indicating protection by ribosomal proteins.

Conclusions:

• Ribosomal proteins confer structural protection to specific regions of rRNA within the ribosome.
• The conformation of 23S rRNA is significantly influenced by its association with ribosomal proteins.
• These findings highlight the intricate interplay between rRNA and proteins in maintaining ribosomal structure and function.