Rapid and simple ribozymic aminoacylation using three conserved nucleotides.

Area of Science:

• Biochemistry
• Molecular Biology
• RNA Catalysis

Background:

• Discovering novel RNA enzymes (ribozymes) is crucial for understanding early life and developing new biotechnologies.
• Selection-amplification methods have been instrumental in identifying functional nucleic acid molecules.

Purpose of the Study:

• To identify and characterize novel RNA enzymes (ribozymes) with aminoacylation activity.
• To elucidate the catalytic mechanism and structural features of a newly discovered aminoacylating ribozyme.

Main Methods:

• Applied a selection-amplification strategy to identify ribozymes from a randomized RNA pool.
• Utilized precise primer removal to select for specific catalytic activity.
• Employed molecular mechanics-based free energy minimization to study the reaction mechanism.

Main Results:

• Identified highly active aminoacylating ribozymes (k(cat) = 12-20 min(-1)) after three selection cycles.
• The active site consists of only three conserved nucleotides and is independent of divalent ions.
• Computational modeling predicted and experimental verification confirmed L-stereoselectivity, 2'-regioselectivity, and independence from amino acid side chain.

Conclusions:

• The identified ribozymes possess an unusually simple active site, suggesting a general pathway for creating small, efficient ribozymes.
• RNA-catalyzed aminoacylation from adenylate is simpler than from CoA thioesters, potentially explaining adenylate-based translational activation.
• These findings provide insights into the origins of translation and the potential of engineered RNA catalysts.