Britannica Sources used in this answer

How can RNA molecules act as biological catalysts?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

Diagram of a DNA polynucleotide chain showing linked deoxyribose sugars, phosphate groups, and nitrogenous bases (adenine, guanine, cytosine, thymine), with an inset comparing ribose and uracil in RNA. — Nucleic acid A portion of the polynucleotide chain of deoxyribonucleic acid (DNA), with an inset showing the corresponding pentose sugar and pyrimidine base in ribonucleic acid (RNA).

RNA molecules can function as biological catalysts, known as ribozymes, by folding into complex three-dimensional structures that allow them to perform specific biochemical reactions.12

While catalysis was once thought to be the exclusive domain of proteins, ribozymes demonstrate that RNA can actively participate in cellular processes. Their catalytic ability is derived from their unique structure: RNA is typically a single-stranded biopolymer that forms complex shapes through intrachain base-pairing, creating helices and bulges. These structures provide specific surfaces that facilitate chemical reactions.123

Examples of ribozyme activity include:
* Self-splicing: Certain RNA molecules can excise noncoding sequences (introns) from themselves and rejoin the remaining ends.1
* Cleavage: The RNA component of ribonuclease P can cleave precursor tRNA molecules to generate mature, functional tRNA.1
* Protein Synthesis: Ribosomal RNA (rRNA) plays an active role in the ribosome, where it assists in the catalysis of protein synthesis by joining amino acids together.43

It is hypothesized that these catalytic capabilities were essential in the early evolution of life, potentially forming an "RNA world" where RNA served as both the genetic material and the primary catalyst for biological reactions.13