Ribozyme Catalysis Mechanisms and Structural Dynamics

Ribozymes are RNA molecules that catalyse site-specific phosphodiester transfer reactions by harnessing precise structural folds, conformational transitions and metal-ion cofactors. Their catalytic strategies centre on general acid–base chemistry, where nucleobases or hydrated metal ions serve as proton donors or acceptors, and on in-line nucleophilic attack, in which the 2′-hydroxyl group aligns colinearly with the scissile phosphate. Tertiary interactions, including pseudoknots and long-range junctions, stabilise active-site architectures and facilitate large-scale rearrangements during the reaction cycle. Structural dynamics range from subtle shifts in metal-coordination and hydrogen-bond networks to pronounced reorganisation of helical stems and internal guide sequences. Studies of diverse classes—from group I introns to small self-cleaving motifs such as hammerhead, twister and pistol ribozymes—have illuminated how RNA achieves catalytic proficiency rivalling that of proteins. Understanding these mechanisms has broad implications for the evolution of RNA-based life, the design of novel biocatalysts and the development of RNA-targeted therapeutics.

Research from Nature Portfolio

Recent studies employing cryo-electron microscopy have captured multiple intermediates of a group I intron during the second step of self-splicing. Six distinct conformational states reveal how the internal guide sequence and peripheral junctions undergo large-scale movements, while active-site metals and key hydrogen bonds fine-tune substrate positioning and transition-state stabilisation. These reconstructions complete a dynamic, atomistic portrayal of intron catalysis, demonstrating how RNA folds can orchestrate sequential chemistry without protein assistance.

Ribozyme Catalysis Mechanisms and Structural Dynamics publication trend

The graph below shows the total number of articles in ribozyme catalysis mechanisms and structural dynamics across all publications each year (not limited to Nature Index journals).

Technical terms

Ribozyme: An RNA molecule capable of accelerating a specific chemical reaction without a protein component.

Transesterification: A reaction in which an ester bond is cleaved and reformed via exchange of alcohol moieties, central to RNA backbone cleavage and ligation.

General acid–base catalysis: A mechanism in which proton donors and acceptors within the active site facilitate bond breaking and formation.

In-line nucleophilic attack: Alignment of the nucleophile, phosphorus centre and leaving group in a straight line, essential for efficient phosphodiester cleavage.

Pseudoknot: A tertiary RNA structure formed when nucleotides in a loop pair with a complementary region outside the loop, stabilising the fold and influencing catalysis.

Inner-sphere coordination: Direct binding of a metal ion to the substrate’s nonbridging oxygen, contributing to charge stabilisation during the reaction.

References

1. Snapshots of the second-step self-splicing of Tetrahymena ribozyme revealed by cryo-EM. Nature Communications (2023).
2. Discovery of natural non-circular permutations in non-coding RNAs. Nucleic Acids Research (2023).
3. Crucial Roles of Two Hydrated Mg2+ Ions in Reaction Catalysis of the Pistol Ribozyme. Angewandte Chemie International Edition (2020).