Crystal structure of a conserved ribosomal protein-RNA complex

Area of Science:

• Structural Biology
• Molecular Biology
• Biochemistry

Background:

• Ribosomal RNA (rRNA) and ribosomal proteins form the ribosome, the cellular machinery for protein synthesis.
• Ribosomal protein L11 plays a crucial role in ribosome biogenesis and function, particularly in regulating translation.
• Understanding the structural basis of protein-RNA interactions within the ribosome is key to deciphering its complex mechanisms.

Purpose of the Study:

• To determine the high-resolution structure of the complex formed between a specific domain of large subunit ribosomal RNA and the RNA-binding domain of ribosomal protein L11.
• To elucidate the molecular interactions that stabilize this complex and understand the role of protein L11 in RNA folding.

Main Methods:

• X-ray crystallography was employed to solve the structure of the rRNA-protein L11 complex.
• The structure was determined at an atomic resolution of 2.8 angstroms.

Main Results:

• A precisely folded RNA structure was revealed, stabilized by extensive tertiary contacts and featuring a large core of stacked bases.
• A key tertiary interaction involves a bulge loop base intercalated into a distorted helix major groove.
• Ribosomal protein L11 directly binds to this intercalated base from the minor groove side, effectively locking the tertiary interaction.

Conclusions:

• The direct interaction of L11 with a critical rRNA tertiary structure suggests its role in stabilizing an unusual RNA fold within the ribosome.
• This stabilization is crucial for the proper assembly and function of the large ribosomal subunit.
• The findings provide atomic-level insights into the intricate interplay between RNA and protein in the ribosome.