enzymeRNA

EnzymeRNA, often called ribozymes, refers to RNA molecules that act as enzymes, catalyzing chemical reactions without being proteins. Like protein enzymes, ribozymes fold into specific three-dimensional structures that create an active site, and their catalysis often depends on metal ions such as Mg2+ and on precise positioning of substrates. Many ribozymes also rely on general acid-base catalysis by RNA nucleotides or bound cofactors.

Ribozymes can act in RNA processing, replication, and metabolism. They can catalyze cleavage and ligation of RNA strands, phosphodiester bond formation, and more. They typically work in cis (acting on the same RNA molecule) but some function in trans with separate RNA substrates. Structural elements such as stem-loops, pseudoknots, and coaxial helical stacks support the catalytic core.

Prominent examples include hammerhead ribozyme (RNA cleavage), hairpin ribozyme, and glmS ribozyme; self-splicing introns (group I and II introns) catalyze their own excision. The RNase P RNA component is a catalytic RNA that processes tRNA precursors, and the ribosome’s large RNA subunit forms the catalytic center for peptide bond formation, a clear demonstration of a ribozyme in biology.

History: the discovery of ribozymes in the 1980s by Thomas Cech and colleagues revealed RNA's catalytic potential, challenging the protein-centric view of enzymes. This shifted research toward RNA catalysis, ribozyme engineering, and RNA-based therapeutics.

Applications include in vitro selection to evolve new ribozymes, regulation of gene expression, molecular tools for RNA imaging and editing, and potential therapeutic approaches. Challenges remain in improving stability, specificity, and delivery in living systems.